ryon137 :
I would like to know what the best card I could get for around $300 or less. I would also like to run more than one on my tower in the future
By 'run more than one' you mean to have multiple cards in SLI?
To do that you will need a motherboard that supports SLI, as well as a PSU with enough power and PCIE connectors.
To make a better suggestion I'd like to know what PSU and monitor you have.
In general, a GTX 970 is probably the best investment because it is very powerful for the money, requires remarkably low power to achieve it, and has 4GB of VRAM beneficial for SLI and all the lazy console ports coming out nowadays.
If you absolutely can't breach the $300 limit, then the best you can get is a GTX 770 4GB
http://www.newegg.com/Product/Product.aspx?Item=N82E16814130948&cm_re=gtx_770_4gb-_-14-130-948-_-Product
or a GTX 780 if you can find one at a sale discount.