Well you wouldn't feed them anything terrestrial lol. Seafood only.
They're quite easy to care for. You can start here: http://www.wetwebmedia.com/marine/in...s/lobsters.htm
Read all the related faqs and articles you think would help on there. Tons of information.
There are really small ones, too, like this: http://www.liveaquaria.com/product/p...555&pcatid=555 These can be kept in tanks as small as 15-20 gallons (try to go bigger as it would be more stable and this sounds like it could be your first set up). These hide a lot, though.
Then there are bigger ones like this: http://www.liveaquaria.com/images/ca...82-lobster.jpg Spiny blue lobsters get quite a good deal bigger at 14" plus antennae length.
And if you're interested in lobsters, have you looked into (or even heard of) mantis shrimp? Now those are some interesting critters...!
I just reread "cost of a lobster" and I may have misunderstood it initially (or not!). I originally took it to mean the cost of caring for one, but if you were thinking of setting up a tank for one of those live "food" lobsters with the big claws, I'd think twice about it. They live in cold water and chillers are $$$, plus they're huge and would require a large tank... Just a lot of work and money to even get the system going.
