Can i purchase an older version license from a third party and use it?

I can not afford a computer and the license right now but I need to run the 32 bit for now. I see that I can purchase an older version for a fraction of the price. Can I purchase a license from a third a party seller and then upgrade later?

You should go to Sketchup.com and read about licensing. If I recall correctly, licenses are not transferable. If that is the case, you wouldn’t be able to upgrade at the upgrade rate. You would have to pay for a new license at full price.