CapnZapp
Legend
Are you sure the problem isn't that you the DM want the players to use more rituals, but that the players are perfectly happy without?Except there's no guarantee that they'll get used on rituals, and a lot of players are going to be hoarders, holding onto the cash for their next big magic item upgrade.
Because money is cheap in D&D. The really good stuff you can never afford - the best gear will always have to come from loot.
The alternative to spending cash on rituals is using it for pretty mundane stuff (items of your level or thereabouts). Things that simply aren't that exciting.
It is that kind of stuff rituals compete against; and in my opinion rituals come out well in the comparison.
However, if your players don't feel that way, don't force them. Remember that in 4E you can do without rituals at all.
Except perhaps raise dead, remove affliction and the like; and even these become optional if you as the DM is generous with NPC ritual casters or simply scrolls.