Gardening both indoors and out can become an expensive hobby, if you let it.  One of the most expensive aspects is attractive pots.  This is also an area in which you can not only save on but also make more interesting by being creative and following the old saying, "ones man's trash is another man's treasure."
An important asset to a planter is good drainage, therefore anything with a hole in the bottom works well: an old watering can, old pail, tool or fishing box, even an old wheel barrel.  Remember the politically correct mantra  - Reduce, Reuse, and Recycle.  By reusing these old objects, not only do you beautify your home, but also you reuse items that would otherwise be in a landfill. (You may also save yourself money, if you pay for landfill space.)  You can also use old baskets.  If the weave is wide, lay sheet moss down before putting in the soil.  Is there a hole in your basket?  Do not use that as a reason to scrap the project.  Think of the hole as an asset.  Plant a vine to drape out.
I have also seen people use bicycles and their baskets or broken chairs as planters.  In the bicycle baskets, moss was simply added contain the plants in the loose mesh and on the chairs, chicken wire was added in place of the seat as a base for the planting.  The most unusual outdoor planter that I have seen was an old boot spray painted with waterproof paint.  It seems that the only rule for alternative planters is that it has drainage and can hold soil.  The visual appeal of these one of a kind planters make them a better choice even if you had the money to                          spend on more traditional planters.