If I ever added up the amount of money I have spent on buying materials to make props and try out ideas I would likely go mad. Then to factor in how much of that was wasted on stuff that didn't work would just cause me to go on a three state killing spree wearing someone head as a hat. (yes that was a Con Air reference. Get over it.)
If I was to stop and think about it all it might actually deter me from creating and experimenting. That, boys and girls, is one of the secrets to my creativity. Never give up and try everything.
The only way to learn is to fail. That is find the ways that DON'T work. Don't let the cost deter you (tho' do be smart and get the best deal. Don't just jump on the first thing you see. There might be a cheaper alternative. (Sometimes you just need a little patience.) Obviously don't spend money you don't have just for the sake of a magic trick, but set aside a little bit here and there if it's super important.
Just don't do the math...