I don't think a bag is all that important esp when compared to a tripod.
When a camera is purchased, it usually comes together with a small sling bag, just use it.
If don't have, just keep inside any ordinary bag as suggested by iamodd.
Last time I started with my haversack and find no problem.
If got no dry cabinet, thats the first thing to invest in.
Actually also hard to advise whether tripod, flash, bag, filters, which ones to get first. You should always deal with the immediate needs or priorities as you go along. No fixed rules, because that's your money and your needs and wants.