Lambert made two signings in January, bringing in Yacouba Sylla from the French second division while also taking Tottenham winger Simon Dawkins on loan.
The 43-year-old says he could not satisfy the fans' plea for him to sign experienced players because Villa were unable to match other Premier League clubs on contracts or transfer fees.
"If you ask me if I’d like to sign a Messi or a Xavi then, Jesus, yes I would have done. But you can only work with what you’ve got," he told The Mirror.
"We couldn’t afford anyone massive, [club owner] Randy Lerner’s been great and I knew the remit. We couldn’t get many loans short-term because of the salaries.
"Is the financial reality we just can’t compete with the Stokes and Newcastles? Yeah, that’s too high for us.
"We’ve got to give the new lads a chance. It’s not like they’re household names coming in and everyone knows them because they’ve seen them play 20 times or 30 times and they know what they’ll get.
"That all comes down to it being a financial thing as well. So we’ve got to go with what we’ve got and give the lads an opportunity to get going.
"The one thing they’ll do for this club is give it all they’ve got."
Villa go into Saturday's game against Everton second from bottom in the league, three points from safety.