My first question is why is the Realtor/Owner willing to sell to you at such a discount? Are there several other condos for sale in the complex? There has to be some value to her, otherwise she would not absorb the discount. If she sells as owner, and not through her brokerage, she may be saving by not paying a broker split.
If you do not have a buyer broker, you do have a greater risk of an oversight on the contract and purchase process that could cost you more now, or later. You can ask the Realtor/Seller to pay your buyer broker fee.
Due diligence for you would include, but not be limited to, verification of ownership and any liens against the property (title), verification of current taxes, review of association by-laws commonly called CCRâ€™s in some areas, review of the association financial strength and preparedness to handle upcoming needed capital improvements, building inspections, wood destroying insect inspections, radon inspections if appropriate for the property, post inspection negotiations, carefully choosing the right lender and loan program, and awareness of any pending changes or discovery in the immediate area which could impact property values. I recommend using a buyer broker to assist with the above. Your representative will also research the comps and discuss the details (average DOM, how many sold, list-to-sale ratios, + ) with you to help you determine a fair price to pay for the property.
If you don't hire a buyer broker, do get yourself an attorney to review the docs.
Best of luck!