I use Etrade Pro. They may fill me numerous times during the day, but only one commission. If there is a commission. For a penny stock it is $4.99. For a big board stock, it is zero. About 90 % of my trades are big board, but I do a few pennies once in a while.
If I can get the bid, I don't mind paying $4.99. After all, 300,000 at $.0049 and $4.99 = $1.474.99, which is still just $.0049166 per share. Better than going to the ask at $.0052 and paying that. If they fill me over two days, and I pay $4,99 twice? Still cheaper.