I know everyone has their own budget, but unless you are trying to make burgers from prime ribeye or filet mignon (bad choices, BTW), the increase in cost is going to be pretty minor, unless you're feeding several dozen people. But more to the point, the improvement in taste, juiciness, and texture is not subtle. On that last point about texture, coarse grind is often recommended when grinding meat for burgers and is NOT what you usually get in the package at the supermarket.
Even if you don't yet own a grinder, if you have a food processor you can approximate a grind if you take partially frozen meat (very stiff); cut it into chunks, and then pulse it, 1-2 seconds at a time, in a food processor. Cook's Illustrated and their TV site, America's Test Kitchen, have tutorials which show how to do this. Here is one of those, from YouTube:
[edit]As I was getting ready to post this, YouTube started playing another burger video. This has almost 26 million views which is astronomical for a cooking video:
[edit2]I just watched the video all the way through. I only posted it because it had so many views. Having watched it, I have two comments: 1) I think he seasons the burgers about a dozen times. As someone who uses salt very sparingly, I don't think I could eat anything with that much salt. 2) He never makes any mention of the meat, what it contains, how it was ground, or how he formed those patties (they look like they were formed in a cookie-cutter).
So, I learned a little, but I don't think I'll be following all of his ideas.
