I would buy that Lotus frame if the paint is good, and resell it. It is a touring bike, and touring bikes sell at a premium. If the paint is decent, you should be able to get at least $100 for that frame, maybe a little more. I have an Eclair myself (I actually have three Lotus bikes right now). But in order to make sure you get a good frame, you need to be able to inspect it for damage. Do you have that knowledge and skill? If not, buying a frame can be a can of worms.
As a broke college student, I would not recommend building a bike, unless you already have the tools/time/aptitude/interest and a pile of parts to complete it. Building your own is never the cheapest route, unless you have all of these items. Even then, it is not the cheapest option, if you consider you could turn the pile of parts into cash instead. Complete bikes are the way to go.
Without pictures, I would say the Schwinn 564. But if it is dirty and the tires need air, I am going to assume it has been neglected and needs some maintenance, so I am probably going to pass, or offer something more like $100. I bought a similar Schwinn (a 434) that was in a similar condition, I paid $80 for it. Why would anyone trying to sell something not even take the time to wash it and put air in the tires? WTF. I would expect a sizable discount. $200, no way. $200 is just about full market for that bike, in pristine, ready to ride condition. A seller who can't/won't even air up tires is pretty sketchy to me. And the 564 uses a pretty unique quill seat post. I would make sure that seat post is in good shape and fits properly. You are not going to be able to find a replacement. Quill seat posts are like gold right now.
I would keep looking. The Flandria does not sound like anything special either.
Last edited by wrk101; 07-20-10 at 09:22 AM.