Here's a list of things we did when short on cash and toys:
Make music/noise with kitchen stuff, like banging on pans with wooden spoons and making instruments out of containers and beans. We had our own band.
Sensory: playing with rice in a tray, cornstarch and water, putting pudding in a ziploc and drawing in it, sand in a bucket, etc.
Dancing to music. That's fun (and tiring...).
Water play outside and in the bath.
Eating meals in unusual places, like a picnic in the living room.
Going "camping" by making a tent with a sheet over a line in the living room.
Reading, reading, and more reading. We worked with books probably two hours a day, some days.
Do everything in short chunks, so she doesn't get bored and things seem fresh. I like the idea of putting toys away for a while, as it also works well with older kids.
Even cleaning up can be fun: put on music, dance & sing while you sweep, do laundry, etc.
Here's a good site with cheapo ideas:
http://handsonaswegrow.com/50-toddler-activities/
This is a developmental age where you want to provide a lot of sensory experiences: touch, sounds, taste, color, and so on.
Have fun! I echo the other poster: don't sweat it that you're not around other kids her age. There's plenty of time for that kind of play, when she's older and more into it. By hanging out with her so much, you're giving her a head start on advanced vocabulary, early literacy (lots and lots of reading time), and a sense of comfort and safety.