Well, Lucas' budget on wasn't that much higher than Jackson. The Rings films started out budgeted at 94 million a piece but then had to ask for me to finish them so its reasonable to assume that each film cost a bit more than 100 million.
Episode I costed 115 million. Episodes II and III were made for 100 million a piece instead of the 115 million that's been reported.
So, essentially both trilogies were made for reasonably the same amount.