I agree with everything Richard Ferguson said. If you think oxyacetylene
equipment is too expensive, then all the other stuff is completely out of
the question. However, do you know that you don't have to buy the tanks.
Most vendors give you a month's free demurage with the purchase of a tank of
gas. If you are doing a lot of cutting, or if you can complete all the work
in a month, the tanks won't cost you anything.

If we are talking about just a very few pieces, and you have to do it on the
cheap, then band-sawing or sabre-sawing are tiresome, but viable options.

It is important for you to know that there is a learning curve with O/A
cutting. You won't just pick up a torch and start making pretty steel
valentines.