The simple, yet truthful, answer to your second question is that you DO NOT have to have lots of money to collect, IF your taste in books is not too expensive to begin with. When put to the text, I can come up with all kinds of wonderful collections one could put together, without a lot of money. One example only, (and an area I do collect in) is a collection of what are called armed services edition books. They are found in many non-book selling places, like thrift shops and antique shops, are often priced at under $10.00, yet even a small collection of 100 titles can give a great deal of pleasure, and be bought for probably less than $1,000.
LOT OF 6 ARMED SERVICES EDITION PAPERBACK BOOKS - All antique Books