If you are looking for a good buy on a tank try checking your cities craigslist, alot of people sell their stuff on craigslist for a good price.
I've gotten two 55 gallon tanks with everything i need for them for only $80 total for the two, one was free with a pine stand, filters, heaters, etc... other one was $80 with a iron stand, heaters, filters, etc....
So check on there for great prices.
As for the JD, I agree you'll need at the minimum a 55g tank or larger, this is because Male JD's can reach 12" and yes I've seen that big in tanks. As for feeder fish, I'd just go with some good cichlid pellets for every day feeding, and some brine shrimp or bloodworms once a week as a treat.
You'll need to keep up with 25% weekly water changes to keep the ammonia, nitrates, and nitrites down. If weekly changes are to much for you, you can do 40% changes every 2 weeks. Don't forget to vacuum the gravel at least twice a month to remove any uneaten food and fish waste.