Cottered cranks are held in place with a pin thru the side of the BB spindle, not a bolt thru the center of the spindle (that's a cotterless crank). These pins can be a pain to remove. Cheaper bikes from oh, pre-1975 used them. If you have a bike with cottered cranks, you will find maintanence of the BB a pain. Basically, you use a hammer and a piece of 2x4 with a notch cut in it. Or a very expensive, no longer made, tool (see them on occasion on ebay). More I won't reveal. You can change the spindle and crank if you want, but you can likely find a better bike elsewhere for less.
If you have cotterless cranks, I'd buy a remover. The only issue is if you're removing older stronglight or TA cranks, in which case you will need a specialized crank remover. You can get a basic one for about eight bucks-- not exactly like buying a headset press or anything like that.
__________________
"It's always darkest right before it goes completely black"
Waste your money!
Buy my comic book!