Hello! I played polo since I began riding. I started riding at a barn that was both a show barn and a polo barn. Polo is aggressive and hard work but is one of the funnest things i've ever done!
I had the same problem, I got bored of jumping around and getting nowhere! Polo was a good break from the average riding expierience. It also is an amazing learning expierience. I learned so much about hard working horses. I became more confident in my riding and was able to handle horses at high speeds. I learned a lot about control and not to mention I developed flexible hands from the hand-eye cooridination.
You don't have to be loaded but it is a fair amount of money, as anything with horses is! Although I personally think it costs less than showing, but it depends on what the pricing is like in your area.
My suggestion would be to see if a local unniversitiy has an interscholastic team? (I live in CT and UCONN offers polo lessons)
If not you'll have to see what's near you.
Here's some things you'll need, you can order them online for the best prices:
Polo helmet with a face gaurd
Polo boots (normal boots will do though)
Polo mallet (size depends on the you and your horses height)
Polo wraps for each of your horses legs
Here are some helpful websites! (: Learning to Play the Sport of Polo POLO GEAR | The Best Polo Products And Equipment