Properly annealing your glass is essential if you plan to create a qaulity product. Working glass creates stress, which will result in cracking if not properly annealed. A kiln will be one of your more significant investments as a beginning glassblower. On the bright side, as with torches, kilns hold their value well. So you can always start small and work your way up to the biggest kiln in the world.
When picking a kiln, decide how large you want your finished product to be, and go from there.
If you cannot afford a kiln right away, you can always use fiber blanket. Fiber blanket will not anneal your glass, but it will cool it down slower, preventing some cracking.