I'm from Korea and there are no spreads in options... When there are spreads, they are very low. It is always like 5.45/5.50. Spreads are always 0.01 until the option price is 3.00 and when it is higher than 3.00, the spread becomes 0.05. So I used to make 3~5% profit everyday by using box spread. But I thought the leverage is too low in Korea and I tried to look at American options and I just realized that their spreads are too big and it is impossible to make any money from box spread. I looked at so many options and calculated in every way and the profit is always negative. It seems like they don't want to give you any free lunch. Are spreads usually that big in the States. Do you know any brokers that provide tight spreads?
Spreads aren't determined by the broker, but by the options exchange. Most smaller stocks have spread issues. The best out there is SPY.