The least expensive model is the base LE6920, which comes with a Rogers Super Stock, plastic M4 handguards, and the Magpul flip up rear sight. Walmart's price should be $1097 for that particular model.
They also carry the Magpul models which are nothing more than a 6920 with a set of Magpul's MOE furniture. These sell for $1167.
The most expensive model is the LE6920 SOCOM, which features a KAC M4 RAS, a heavy profile barrel, and a MaTech rear flip sight. These sell for $1400+.
"Si vis pacem, para bellum" - If you want peace, prepare for war.