Retinning isn't cheap, but it's not all that expensive either. In addition to tinning the pan (or pot), the tinner will usually clean the copper to new condition. Here's a link to the only place I know (the same place referenced by Dillbert), which does any kind of real business retinning copper: Pricing cost for retinning refinishing copper cookware pot pan
Copper is beautiful to be sure, but tinned copper requires some care cleaning (mostly keeping it away from destructive hands), and the bottoms require a lot of work to keep clean and polished.
Copper has the reputation of being "the best." But my experience is that compared to other good cookware, copper doesn't offer enough significant
performance advantages for performance alone to justify its additional cost and maintenance. One man's opinion, your mileage may vary.