I concur with the original poster's rationale for budget (as opposed to low quality) tuners, but for those building or repairing for customers, it's worth considering the cost difference in providing that customer with the option for speedy replacement.
Where tuners are purchased may matter in terms of eventual repair/replace. Purchase a set of expensive Schallers from the average eBay seller and you will still get the lifetime warranty... but it will take six weeks to exchange the tuners, and you will be shipping the tuners back at something like $15-$20 out of pocket for shipping and insurance. Purchase that set or any other tuning machines sold by StewMac and you'll have replacements in hand within 3-4 days, and may or may not be sending the defective tuners back on a return authorization.
Based on my experience and others in the shop where I worked for a while, Stewmac does not have a time limit on replacement of defective products, so that stands in contract to Amazon, which has a generous replacement or return policy, but is strictly time limited... after that, it is a manufacturer warranty and return policy issue.
Looking at the cost of this level of post-sales support, two sets of the Wilkinson mini ovals in chrome run about $58 from Amazon, while two sets of Grover Minis from Stewmac will run $120 (at retail), so just a bit more than double the cost of the Wilkinsons for some improved level of service over time. For a builder working at or below minimum wage to build their way out of journeyman status, that cost difference and hit on total material costs is significant. As the gentlemen I worked with at Greenridge noted, tuner costs may run 30% or more of wholesale materials BOM, and may be the most expensive single item on that BOM, so smart choices apply where budgets are limited. It may be cheaper over time to use a few core tuner configurations and just pick up a few extra sets in case of need to replace a machine or two.
We frequently doubled up on tuner orders and as a consequence of that policy had a fair number of sets available for urgent replacement or while-you-wait upgrades. But uncommitted inventory is as much an opportunity cost as it is a potential goodwill building expense for a shop just starting out, so not necessarily wise or even financially tolerable. Even now, I find myself 'leveraging' my former shop's stock... but in fairness to the gentlemen, I pay with lemon bars and my sparkling company, so in my opinion, a very fair exchange.
