The flat nose bits (like the cobalt or hi-speed kind) that I have used are yep awful expensive. Think I may have put a pic of that on his other thread. You only get one cutting surface for the $. I have like a hundred dull ones.
Another thing I use to remove welds is a 3" air cutoff tool. You just grind away the top layer of metal over the weld. But thats just for worst-case scenarios because it removes so much metal. Not what you want if you're welding the same part back on.
I see the smiley now, lol.
I forgot to mention that when removing a spot welded part, to go ahead and cut all the welds before starting to pry the part loose.