I found a really cheap way to get plants is to buy them secondhand! Lots of times, you can find plants at yard sales and estate sales if you keep your eyes peeled for them!
Last year, I bought this tree at a yard sale of a guy who was moving away. He had it for 10 years! I kept it inside this whole past year but it didn't seem very happy, so I moved it outside this spring. I re-potted it a few weeks ago and I'm keeping an eye on it and hoping it flourishes!!
A few weeks ago, I was at a Family Tree Estate Sale and discovered a little plant outside on the covered porch. I brought it in and asked if plants were for sale and Melissa said, "Sure!" I bought it for $2 and she pointed out that it had a tag on it that labeled it as "easy care." Then she said, "It must be easy care because no one has lived here for 2 years!" WOW! It's doing really well after I re-potted it--I'm still looking for a nice vintage planter for it.
Plants are normally out in the yard or on porches at sales, so be sure to look around if you are interested in buying them!