I would never have started leatherworking if I had realized how expensive it would be. Good thing I had no idea, because I love it! It cost me about $1200 the first year, and I was spending as little money as possible, and wasn't even getting nice tools. So yeah.. it can be expensive. But it's also not necessarily the best idea to dive in and buy tons of expensive tools without trying some things first.
Also, if you look through this forum, you'll find a lot of old threads (and threads from last week) where people ask for tool lists and tips for just starting out. See what you can find. This place is even better than Tandy, in terms of learning.
Lastly, leather is very popular, and if you make good products, which you are likely to do, since you come from an experienced sewing background, you'll be able to make the money back very quickly.