There are two answers, I can give you. One if a property is listed at 100k, you can still put an offer on it. I will tell you it's very competive right now, there are alot of big investors buying up properties in that price range and inventory is low. So, some buyers are actually coming in higher on their offers.
Depends on the type of listing too! If it's an approved short sale. Sometimes a listing agent will say it's an approved price. That means the bank will not accept any less for the property than 100k. But an approved short sale does have a time frame too so it's best to have an experienced buyer's agent help put your offer together. They can contact the agent and find out how old the approval is for you.
I hope that answers your questions.A buyer's agent can tell you what tell you what the property is worth and help you come up with the best offer. And remember the buyer's agent is paid by the seller! If your in need help.... you can check out my buyer's presentation for myself and company at www.c21be3.com