There are not one single tree that naturally grows indoors. It is possible to grow a very few species indoors, but they will never thrive. All of us grows trees outdoors. A very few of us keeps a ficus indoors in winter. But always outdoors in summer.
If you want to grow bonsai indoors, Ill recomend to get a jade tree from your local garden center. Not really a tree, but possible to make it look like a bonsai. Going for any other species indoors all year will just make you dissapointed and leave the hobby.
I have somewhere around 120 trees in different stages of development. Out of them 4 is purshased as bonsai, rest of them is garden center or colected materials. Out of the 4 ones I bought as bonsai, just one is from a place that have a regular stock of bonsais. The other 3 is from very temporary stock or from other hobbyists.
To cunclude: bonsai is created not purshased. Bonsai is an outdoor hobby.