No matter how little software you sell – having an own web site with a top-level domain is important. Not only does an @company.com email address look professional, but it also allows you to join the PEF club.
GoDaddy, a pretty nice domain reseller (ask your host if they have DNS servers of their own, however), currently sells domains for just 7$ a year: the discount code gdp0820c is all you need to have.
P.S. The domains drop with free POP3 email (one account) and basic, ad-supported hosting…
P.S.2 I am not affiliated to GoDaddy in any way except as paying customer.