Why the Cheapest Siemens PLC Quote You Get Won't Be the Cheapest Order You Place

The Cheapest Siemens PLC Quote You Get Won't Be the Cheapest Order You Place

I'm the office administrator for a 220-person metal fabrication shop. I handle all facilities and MRO purchasing—roughly $1.1M annually across 14 vendors. I'll just say it: the lowest number on a quote sheet is almost never the lowest number on the invoice at the end.

That applies to valves, to floor mats, and to the Siemens PLC hardware that keeps two of our production lines running. I don't shop PLCs on sticker price anymore, and I think anyone who does is setting themselves up to pay more in the long run—not always, but more often than the price-first approach suggests.

Where the Cheap Quote Costs You—A Power Supply Story

In 2022, I moved our S7-1200 power supply orders to a new distributor who quoted us 18% less than our long-running supplier. Straightforward savings, I figured—easy win for the quarter. Three months in, a technician asked why he had to make a second trip to the supply cage for the terminal block and DIN rail clip. Turns out the new distributor's Siemens PLC power supply price didn't include mounting hardware that our previous supplier had bundled in automatically.

We weren't lied to. The quote was accurate for what it covered. But "power supply" meant a different set of components to them than it meant to me. Same words, different meanings—I found out when hardware went missing from the box.

My effective cost after sourcing the missing parts landed about 6% higher than the original supplier's all-in number. Not catastrophic, but it's the pattern I keep running into: the low quote was accurate, it just wasn't complete. (Note to self: put "verify included components in writing" into the standard RFQ template—I keep forgetting to do that.)

The Causation Runs Backward on Industrial Pricing

People assume vendors who charge more for Siemens PLC gear are overcharging. I used to think that too. What I found is that vendors who deliver reliable, fully-specified, technically complete parts can charge more because the quality and completeness justify it. The causation runs the other way.

Our current core supplier for S7-1500 modules runs about 12% above the lowest quote I can find on a price comparison site (as of January 2025—your market may differ). They include commissioning support, handle warranty claims in-house, and answer technical questions in a Slack thread rather than pushing me toward a ticketing portal. I've stopped pretending that's just a nice-to-have. It probably saves us 3 hours a week during commissioning windows—time our engineers would otherwise spend digging through documentation.

The flip side matters too. In 2024, our Mexican integration partner sent me a document labeled "ventajas y desventajas PLC Siemens"—pros and cons, no sales gloss. It honestly laid out where the ecosystem shines and where the platform has real trade-offs (per-seat licensing cost is no joke, for one). I've kept that document as a reference because it gave me a working picture of total cost, not just the hardware line item.

The Same Rule Applies to the Oddball Requests

My request queue on any given Tuesday includes things that have nothing to do with each other. One recent day: a Siemens S7-1500 power module replacement, a quote for a steampunk control panel for a marketing trade-show booth (they wanted brass gauge casings and copper piping—I still don't fully understand the vision), a warehouse question about who sells lithium battery chargers nearby, and a facilities request to weigh in on Kohler vs. Generac home generators for the security shack at the back of the lot.

Each of those looks unrelated. But the same test applies: get the full picture of cost before you sign. The steampunk panel vendor quoted a low base price but—only after I asked—disclosed that custom brass fabrication was billed hourly at a rate higher than the entire panel line item. The battery charger vendor down the road quoted competitively but couldn't produce a proper invoice, and our finance team would have rejected it. The generator question? The two brands' published maintenance intervals—every 200 vs. every 250 running hours depending on model, to simplify a quick comparison—matter more than the purchase price when the unit lives in a shack that gets dust in its cooling vents.

Transparent pricing is the same test everywhere: can I see the whole number before I sign, or am I going to find pieces of it later?

But Doesn't the Budget Force You to Pick the Low Bid?

Fair objection. I've delivered bad news to our VP of Finance about overruns before, and I don't want to do it again. Tight budgets are real, and the purchasing function exists partly to protect them.

Here's what I've learned: the price-first approach creates budget surprises. When I bought the 18%-cheaper power supplies in 2022, the savings showed up in one line item and the missing hardware showed up in another three months later. Net effect: a red flag in the quarterly review and a conversation I'd rather not repeat. The "higher" all-in supplier would have produced a cleaner number and less work for me.

The other argument I hear is that sticking with a pricier supplier for ecosystem reasons is just paying a premium for branding. Sometimes that's true. To be fair, there's a lot of brand premium in industrial automation that doesn't translate to better outcomes. But when I compared our S7-1200 platform costs on a 3-year cycle—counting support response time, warranty handling, and the cost of one unscheduled line stoppage—the "expensive" supplier came out ahead. Not dramatically, but consistently. During a retrofit last spring, they sent a field engineer to walk our maintenance crew through wiring. That's not branding. That's cost avoidance.

Restating the Point

So this is my position, and I'll hold to it: the cheapest quote is almost never the cheapest order. I got into trouble in 2022 by treating the sticker price as the whole story, and I suspect most industrial buyers who are honest with themselves have a similar story. The cheapest-to-buy option is a different animal from the cheapest-to-own one—and if you're the person signing the PO, you should be thinking about the second.

The vendors I trust most aren't the ones with the lowest numbers. They're the ones who list what's not included before I ask. That's the test I run now, regardless of what I'm buying—whether it's a Siemens PLC power supply, a copper-piped trade-show contraption, or a generator for a shack that gets dirt in its ventilation.