Donald Trump -- I'm Not Upset I Didn't Get The Bills ... Bad Investment Anyway

Donald Trump tells TMZ Sports ... he's not upset that he wasn't able to strike a deal to buy the Buffalo Bills -- because it would have been a bad investment anyway.

Trump was one of the big names in the hunt for the NFL team -- which ultimately sold to business mogul Terry Pegula for $1.4 BILLION.

But when we asked Trump about the situation Wednesday night, he didn't seem bothered by it at all ... telling us he didn't think it was a great financial move anyway.