Before moving to the United States last year Rees-Zammit had been linked with a switch to a club in France’s Top 14.
The winger – who scored 42 tries in his 77 games for Gloucester and 14 tries in 32 Tests with Wales – is widely regarded as one of the standout attacking threats in European rugby.
Lam says Rees-Zammit had a number of offers, some which were more lucrative than what he was being offered at Ashton Gate.
“What I really enjoyed about the whole thing is that he could have gone anywhere for lots of money,” Lam said.
“I know there was big money out there and I’d say our offer is nowhere near what people might think it is.
“What I liked about that is that left it purely on him to decide if he wanted money.
“He probably had four or five other offers that he could take, but if he wanted a good rugby programme and a style of rugby that gets him back into the game and obviously gives him the best chance to play for Wales again, which is important to him, but playing good rugby for us, that was the main thing.”
