How do I get my domain name back if I forgot to renew it?

If you really want to get your domain back then you have to purchase it again. But I would suggest that you buy new domain. You an use a .NET any domain extension that you want. To avoid the thing from happening again, it is wise to opt to Auto Renew Protection. Keep your domain name secure by automatically renewing your registration. Never worry about forgetting to do it manually. You'll keep your domains, hosting, Web site builders and other products where they belong: in your name, in your account and under your control!

You have lost control of it now, and seeing as you are (probably) not a celebrity... I doubt you can get it back... you would be better of paying the $100 or just acquiring a different but similar name - maybe buy the .NET or .INFO version Unless you can show that the company are deliberately profiteering from the transaction, there is not really any action you could take (such as someone who buys a domain related to an up and coming celebrity name with no other justification). Although there is (IMHO) an element of profiteering, because I doubt they just 'happened' across the name - I expect they bought it as an 'expired' domain, the $100 price tag is not so large as to be out of reach of the average Joe....

Buy it back or create a new one with a slight variation on your name. Like if your old one was johnsmith.com make the new one john.smith.com. Best wishes!