This could come down to cultural differences. I too don't really have many friends and we just do a bar or dinner. Usually someone pays for the birthday person's meal while the rest pays for themselves. If we are at a bar, everyone usually buys the birthday person at least 1 shot/drink.
I have not been invited or invited people to something that requires an upfront fee like Topgolf since high school in which the birthday parents usually covered the costs. However, knowing how at least my area/group of friends work it would be that individuals pay for themselves. If a friend cannot afford it, usually someone will help them out.
It just depends on your friend dynamics. If you can afford it and are willing to pay for all then by all means do it if that's what you want! Another group of friends would usually just rotate who pays for the whole thing. One person would pay for the movies, the next time we all hang out another would buy a round of beer, the next time someone would buy tickets to a game.
If it is expected that you pay but might not have the cash to, just post as part of the invitation that you will pay the $60 fee (you said no more than 2 hours at the assumed average price of $30) and that if anyone wants to help chip in to cover costs are more than welcome to.
From my experience though, I have never gone to a birthday completely free. Either buying a drink, a shot, buying their dinner, chipping in to pay for their entrance fee, it has always been something my group has done to take care of the person (I mean hey it is THEIR birthday after all).