you might need a serger as well as a good sewing machine, bernina, phaff, husqvarna all have good machines, check them out and compare features and prices. you want a one step buttonholer thats for sure.
Go to a reputable dealer and ask about used machines that have been reconditioned. They'll be cheaper than new, but probably better made than the junk that Walmart sells. Walmart machines tend to be inferior, and you won't be able to get anyone to se...
Call the local fabric store in you area and ask to speak with someone about their sewing machines, find out if they sell viking and ask them what they think it is worth. Also you might try looking in the yellow pages under seamstress and calling them...