I think the individual transactions can be quite small. You just have to commit to making $5 of them because of the non-micro-transaction handlers. Apparently

I think the individual transactions can be quite small. You just have to commit to making $5 of them because of the non-micro-transaction handlers. Apparently you can buy gear. I haven't played TF2, but from my "too many" TF days, there were many times I'd have gladly payed $0.10 to see a sniper lagged for just 200ms.