While I do not think seeing "Believe" after "O" would be repetitive, I think it may be disappointing. There are three kinds of shows in Vegas: Major Productions like "O", Headliners like Cher and Standard Vegas shows like, well, like everything else. You cannot really get discounted tickets for Major Productions or headliners but you certainly can for the standard shows.

So, since you are already seeing a Major Production show, I recommend you go to see one of the regular shows. A great place to purchase discounted tickets is a place called TIX 4 Tonight. They sell half-price same day tickets to shows that are not sold out. Note: Major Productions and Headliners are always sold out because the Hotels reserve large blocks of seats for high roller comps.

Good Luck!

*References : http://www.tix4tonight.com/

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