First of all, the keyword "mountian" is spelled wrongly; the correct spelling should be "mountain". Also, when the last keyword of a domain describes a product or service, the last keyword should be in the plural form. So the ideal similar domain will be "MountainHats.com".
Because of the spelling mistake of "mountian", it is my opinion that the domain is worth reg fee, if any.
I always advise newbie domainers to be very selective of the names they buy or register. Domaining is a hard and saturated marketplace. To give some insight on how I select my names, I search through 100 pages of domains and out of these, the no of names that I finally register or buy range from 0 to 2. It is not easy quick money, that's for sure.
If you are unwilling to commit the level of effort that I do in searching for names, it is my opinion to best redirect your efforts to other probably easier ventures.