The price sounds about right for a U-08. Many of these bikes were sold in the late 60s and early 70s, I still see a lot of them around. People generally refurbish them or convert them to fixies. Going price? My guesstimates are: cheap at a garage sale (l.t. $25); probably in the $50 to $150 range at a second hand shop in as-is original condition; maybe up to $300 refurbished, depending on components used and amount of work done.

The original rack was probably a Pletscher. They may still make them, I've seen their name on kickstands recently. Not hard to find used, either. Right now eBay's got a used one at $4.99 and an NOS one at ~$25.00. Although better racks can be had these days...

Unless you really want to keep the bike all original, I'd replace those rims w/ a good set of alloy rims (or build a set of new wheels and just keep the old ones in storage) and also replace the front der.

Nice bike. Brings back old memories!