SD mini card for Garmin Etrex Legend Hcx

Santa brought me a Garmin Etrex Legend HCx for Christmas. I was looking at the garmin website and see a miniSD card and saw the Inland lakes south central - has Missouri, Miss, Ok, etc. Are there other options? This is my first gps unit and I'm a novice at using them and the software that's available. What do you guys think? I appreciate your help. Give me a holler if you're ever up at Truman, and we'll go jerk some slabs. I figure I'd better get some of my spots marked before the trees rot away. . . .