If the question is "HOW MUCH would you be willing to pay", then besides the first two given options, what can "Other" possibly mean?
Because obviously "Less than or Equal to 50 Dollars" is inclusive of "0" (i.e. not willing to pay anything).
I think that people tend to forget that tools are expensive. Especially if you're using purchased engine rights (Unreal) that in turn utilize specific in-house dev-branch components. They have to be tailored to the game in which they are based, they have to be optimized, and they typically necessitate a ease of use factor (RID and UI redesign) that the developers are not accustomed to. Typically at least.
So, if you want early access to the mod tools, you better be prepared to donate a much larger sum of money. At least that's the route I'd go.