NLL.us is still regfee according to http://www.3character.com/priceguide.html However mm is good and it is premium letter so low to mid $xx. I personally wouldn't count 3mm being an abbreviation because that makes domains like 17kg, 32lb, 97c sound valuable which isn't necessarily the case, just my 2cents anyways.
Thanks a lot... It is good to know it is worth more than the amount I paid to catch this expired domain(low $xx)...