Hello Devon
I am a cajon player and have been busking with the cajon accoustically all over london and the UK for the past 5 yrs, ever day! At first my hands did hurt, quite a bit. I was very much aware that the main reason was due to the crap quality of my first cajon (it was really not good at all), so I speedily invested in a new and better cajon. That pretty much cleared up a lot of the pain issues in my hands, however, I noted that as I practisied and improved on my technique on the cajon (practise at home to slap the cajon right, very simple, repetitive techniuque ex, you can find some on my all about cajon website) the pain got even less. what practising good technique does is firstly the obvious, gives you much better technique, but secondly, regular, constant practise (this is apart from performing) really toughens up your skin on your hands, which gives you more volume and also helps reduce the pain from playing cajon accoustically on the street (with a full band, amplified up as well, might I add).
So once I had enough money I invested in a really good cajon that specifically has a super bass and a loud sound, and I have ever since had to learn to play a bit softer than usual (as I had taught myself to slap so hard with the bad cajon and it was really a bad habit with the good cajon as firstly it kills the good resonating sound and secondly is way too loud!) So get a good, LOUD, LOOONG endurance cajon if you wanna busk accousitcally without pain. I got some great one's stocked on my website, and I have been busking with these for the past 4 yrs, never looked at others again as I am happy with these!
Otherwise get a mike and amp and mike yourself up!
Hope this helps!
Ohh and I must add that there seems to be a certain amount of backpain you have to go thru for the first 2 - 3 yrs of busking/performing on the cajon daily. I remember having to have to stop after a few songs and getting really tired in my back after just 5 min of playing. Remember to take breaks when you are going to play long, and just puch thru, I can now play for about 3 - 4 hours non stop (without issues of my back getting tired) I suppose there's muscles that have to learn and be built to support your position when playing cajon. This will take time and there's no shortcut for it.