normally (unless your broker has some weird “minimum commission rule” concealed in the small-print) they’re absolutely tiny, exactly as they “should be”
commissions quoted are normally “per full lot”, so even if you use a broker with both spread and commission, the dealing costs on a cent or micro account will be almost too small to notice: for example, if they charge $6 per lot commission, and you trade 0.01 lots (one microlot) the commission-fee on that should be $0.06
they all have some kind of “support” (hopefully “live chat support”) and you can always ask them to clarify in detail
but if your concern is that you’ll end up paying disproportionately high commissions on a micro account, the answer is “you won’t” - they wouldn’t be able to keep their customers, that way 