A feltboard and a pocket chart are great investments in terms of something basic you can use for multiple uses. The pocket chart can be used for matching and sorting, just cutting seasonal pictures from magazines and mounting or stick to shapes, letters, etc. You can then use the pockets for telling stories by putting the figures in the pockets. Feltboard works the same way and both are quiet actitities depending on how many sound effects the kids add.

Just be sure that what you buy aimed at the older kids is stable enough for the little ones such as a stroller that a one year old might use to try and stand and push. Or a doll playpen they might fall down and collapse the sides on - ie a plastic laundry basket makes a great playpen for a doll.

I don't find my group really dresses up at all since they can barely do their own shoes or a sweater on and off. They are more interested in making the dolls do things over them dressing and doing. They pretend to have tea without dressing for a tea party or be a doctor without wearing scrubs. Keep empty plastic bottles, containers etc. I am gradually trying to replace my plastic/wooden playfood with fabric/felt foods but a few foods at least are nice - just make sure they aren't small enough to be chocking issues for the toddlers who might get into the doll area too.

Puppets is something you might want to look into. Even the dollar store ones - especially animals ones are great. Animals of any kind. I have a large collection of dinosaurs from the dollar store they love and yes sometimes the dinosaurs and the cows and pigs are all part of the farm.