Terrell Owens -- Birthday on a Budget

Terrell Owens turns 38 today ... and he's getting wiser with age ... because instead of dropping a fortune on a birthday blowout ... the financially strapped football star has decided to celebrate on the cheap.

For years, T.O. would spend thousands of dollars to honor his special day with high-end bashes all over the country.

But now that he's low on green ... Owens has decided to do the responsible thing ... and have a low-key birthday dinner with his GF and some close friends.

Owens has been telling friends he feels "humbled" by his recent financial troubles ... insisting he's "more grateful for those that love him and have stayed in his corner."