2000 Ram 1500 A/c

I Had My A/c Recharged Last Year, 8 Months Later It Is Dead Again, Any Thoughts On What I'm Looking At.the Shop I Had Recharge It Also Put In A Sealant In Case There Was A Leak, Worst Case Thaey Told Me I Would Have To Replace The A/c At Around $1100, Does That Sound Way Out Of Line.