how do I play a rental on apple tv

Through home-sharing. Make sure both ATV and iTunes have it enabled. Computer must be on and running iTunes, then go to the computers section and you will see a rentals sub-menu.

Has the rental finished downloading to iTunes?

Yes

Having same problem but do not have a computer. Only have iPad, apple tv and iPhone. Is their a solution without buying a $1000 computer to watch the $3.99 movie I rented?

Best to rent directly in the future then

Thanks vazandrew but I did rent directly from my apple tv. It has the latest update and I am able to watch previously purchased movies. The rental did temporarily show up... Started to down load and then said my devise was not authorized. Then it crashed. Now when I try to rent it again it says that it has already been rented and I should go to settings and downloads. There is no download button and the closest thing I could find was check for rentals under iTunes... But it just sits there and spins for an hour and never gives another option.

Thanks in advance for your suggestions.

Devin

After about 3 hours it finally showed up in my rentals. Just a terrible way to rent a movie!

I can't download on my macbook because I need to delete some files first. If I try to buy it again through apple tv, will it already know that I bought it and just download on apple tv for free? Music does that between devices so I'm thinking tv should do the same but I don't want to pay for the movie twice.

Rentals are not purchases so they won't be available in the cloud. You have 30 days before expiry (the clock only starts once you hit play) so you have time to make room and download.