Probably true for some things. Depending on what CPUs you want it could be as cheap as 80 bucks, or, up to 200 as you said, but the same would hold true for a white box SM build. AFAIK Dell hardware isn't picky about what drives you put in the chassis so you don't need to buy branded stuff.That would be a very bad idea. The accessories for Dell servers are costly. It's always a best bet to buy a fully configured Dell server instead of buying it as parts. For instance, power supplies cost as much as $130 each (750W~1100W) used. Processors would be costing at-least $200 for a pair. Dell branded HDD or SSDs are way too overpriced even for used ones. By looking at the listing picture, even the PERC card is missing, so that would be $160 for a decent H710P. 1333Mhz DDR3 ram would cost around $12~$15 per 8GB stick. Additionally you might also want to consider getting rails and front bezel.
I have a basic R620 bought directly from Dell and I have spent more money on the accessory upgrades than what the server is worth. It's honestly not worth the hassle.
You could probably get a H710 mini for about 65-75 on best offer which is about what most people would pay for a similarly priced RoC adapter. Another option is an H310 mini instead which is what I would think most users would go for since there is a lot of buzz right now with converged storage and other things like ZFS/ceph, and, which is -about- as cheap as the standard H310.
PSUs do seem to cost a bit but again it's all about sifting through best offers on ebay. I don't think building a few out or even just 1 would cost that much to be honest. If I had to guess Fritz probably has a few dries and RAM already.