The Spaniard has enjoyed a solid first season at Goodison Park by keeping the team in the hunt for European football.
However, Baines believes that the squad must be improved at the end of the campaign if the Toffees are to keep up with their rivals.
"I'm sure the manager will be looking to keep investing and keep improving the squad because every year that's what everyone else does and I think to give him a chance to improve us to that level then he's going to need money to invest," the England international told Sky Sports News.
"We're working on what we've got here and what we've got at the moment I think the big teams have a lot of money to spend and they spend it every year and they improve every year so we'll have to do the same."
Everton return to Premier League action on Saturday when they entertain Martinez's former club Swansea City.