Bale, 29, has long been linked with a return to the Premier League, and admitted after the 2018 Champions League final that he could leave the Bernabeu ahead of the 2018-19 campaign.
United are believed to have a long-standing interest in the Welshman, but Bellamy has played down suggestions that his countryman could move to Old Trafford.
"Where could he go? Man United can't pay his wages, nobody can. There's only one club that can pay his wages," Bellamy told the Daily Star.
"That's the world he's in at this moment. The wages he is he'll have to take a massive wage cut to go elsewhere. And I'm sure he would do but realistically then is someone then going to go and buy him? How can a club go and spend £80m, £90m?
"I know Juventus did for Ronaldo but Ronaldo's a different purpose, that's a different world of business. But Gareth, how can you go and spend £80m,£90m, £100m for a player you're not going to get any return on?
"Maybe as part of a part-exchange deal but Gareth won't be part of any part-exchange deals, he's too good a player for that. So I just don't see it being a possible move for anyone to get anywhere near."
Bale has scored 88 times in 189 appearances for Madrid in all competitions.