Best reliable place to purchase cheap domains?

I like GoDaddy.com.

1and1.com is another good option.

I second @marinelife and also want to tell you to ALWAYS do a web search for “godaddy promo code” there is always one out there to get your domain cheaper. (I paid $7.49 instead of $10.00 for my last one)

GoDaddy’s been around long time and holds prices down and has reliable service 24/7
Hey Dog and Marinelife—seconding your opinion. Dog thanx for tip on promos.

I use hostway.com

I only pay about $6 a year.