imo the fair price for blueprints is the NPC sell order price. Most of the bpos on contracts sell for multiples of the NPC price. Example a researched cruiser bpo tends to go for ~250mil, and they sell for ~80mil. research costs are pretty low, but it is going to take a while to research. A cruiser BPO (without skills) takes ~118.5 days to fully research one attribute to 10. That said you can go to 8 in ~21 days. I have an alt with the research skills maxed out, but I don't really want to waste his slots on research as I can use his slots for invention, although those skills reduce research time by a decent bit. I forget which class of bpos it was but on low trained alts I could only research to 8, but with skills I could go to 9.

maybe you need the bpo now and will pay for it, in the grand scheme it isn't really a huge difference, but I'm not paying that much for a researched bpo, I have enough researched bpos just sitting around that I'm already not using :p

Jita sells most caldari ship bpos so that should give you a general price for bpo prices. Frigs: 2-3mil, destroyers: ~8mil, Cruisers ~85mil, BC 500-600mil, BS:1-1.6bil

low value bpos are pretty easy to move in a travel fit ceptor. since you have to go to their homelands to get the best prices that is how I would pick them up. just make sure you keep moving and fit enough buffer a thrasher can't volley you. I wouldn't worry too much about losing a 100mil or so. more valuable bpos I would suggest something with a cloak. Blockade runners are nice as you can put some buffer on them, and they can't be scanned.