As a breeder, there is a small part of me that shudders when people price shop puppies. While I understand completely that finances are an important part of life, the breeder in me knows what happens when people price shop for puppies. There are "breeders" and there are people who simply "breed dogs" - there is a great amount of difference between the two, and like most things in life, you get what you pay for. Not the time or place for the "why's" to my statement.
So ... my best suggestion is to first do the research on which breed is right for you, then contact the rescue groups for that breed(s) and inquire about available dogs. Typically, most breed rescue groups require a small fee (which is often tax deductible), and will interview you to make sure that your home is suited to a dog, and to match the right dog to your needs/desires. Rescue people are generally very adept at making sound decisions about which animal will work well in your situation (ie a dog that is already accustomed to cats for example).
here is the link to the National Club's (West Highland White Terrier Club of America) rescue site.
http://www.westieclubamerica.com/rescue/index.html
here is a link to the Maltese rescue site (American Maltese Association).
http://www.americanmalteserescue.org/
And in case you wish to consider another breed, here is a general link to American Kennel Club's list of ALL rescue groups that are affiliated with an AKC member breed Club.
http://www.akc.org/breeds/rescue.cfm
Good luck in your search. I hope you are able to make a needy dog a good home.
Sue