Crib Help Please

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My husband and I have been looking at baby cribs and we like the idea of having one that converts.  This will be our only child so we don't want to spend a ton of money on a crib that we will use only once so that is why we like the convertible ones.  My question is do convertibles work well?  Also where is the best place to buy a crib. I haven't been too impressed with the cribs at wal mart.  We live near Wichita, Kansas and have access to two baby's r us but no Pottery Barn or Ikea.  I do not want to buy a crib without first seeing it so I do not want to buy online.  Any help would be greatly appreciated!