When you want to buy or sell any property, as much as possible, don't go through any middleman if you want to get the best value for your property. Normally middleman will markup the price of the property to earn some commission from it. Most of the time, VERY high commission.
If you plan to buy condos in Phoenix, check out CondoCompany.com. They are the number one searched condominium dedicated site on the Internet. At CondoCompany.com, they have this program called the CondoList whereby various types of people such as Realtors, Owners, and Developers are allowed to list condos for sale in Phoenix. This allows potential buyers searching for Phoenix condos to find the contact information of the listing agent or owner of each condo, bypassing any middlemen.