Suppose you knew how to build a time machine (just for fun). If I asked you to make me one and I said I'll pay you how much $ would ya want?
The cost of supplies plus 25%
1 million trillion dollars. :P
I'll just make you pay me a few trillion dollars everyday...
All of it
None . cause you could could change the past and hurt the present and future.
I could do it. But I'll need around $500,000 dollars for the lithium fuel, flux capacitor, fusion coils, and various construction parts.
20 bucks tops
one million dollars!, (austin powers reference)