There are several resources available to you in locating Boulder homes for sale.
The most common way to identify properties listed for sale by realtors in the MLS - Multiple Listing Service.
Email Me New Properties As They Are Listed On The MLS
In a small percentage of cases, a property is marketed directly by the homeowner. The properties ae commonly known as "FSBO's - For Sale By Owner". These houses are generally marketed by Classified Ads in the local newpaper and "For Sale By Owner" signs in front of the house. If you desire to purchase such a property, I suggest retaining a realtor or an attorney to represent you in negotiations and contracting to minimize potential problems.
In times of financial uncertainty or turmoil, there are properties that are foreclosed-on by lenders. The lender becomes the legal owner of the property and looks to resell the property to recover the amount of the money they have lent. Sophisticated investors often review such properties for potential investment opportunities. These properties are usually sold "As Is" meaning that the lender offers no assurances or warranties as to the physical condition of the property or the legal title before their ownership began. While the purchase of foreclosed properties may provide an economic windfall, "Buyer Beware" as you proceed.
If you are delayed in purchasing your Boulder real estate or plan a renovation before moving in, you may require temporary rental housing.