Keep in mind that the listing agent only represents the sellers' interests, so they would be much less likely to negotiate the best deal for you. Agents that represent the seller are required to be honest and disclose any material facts about the home; however, they want their sellers to get as much money for the home as possible. Sellers typically pay the commission for homes listed in the MLS, so having a buyer's agent who can do all the research for you for "free" in this current market would definitely be to your advantage. There's also the chance that the seller is unwilling to accept a contingent offer in the first place since most homes that switch from "active" to "contingent" have less showings. I have a listing in North Ridge currently where the sellers OK'ed a contingent offer, but since changing the status to contingent, there have been no showings at all.
There's also no guarantee that the sellers would allow "their" agent to work the buyer in the transaction since some see it as a definite conflict of interests. Many listing agents automatically refer that buyer (for a referral fee) to other agents they work with because it seems more fair to both sides of the transaction to have their own representation. In some cases, it is true that the listing agent could tinker with his/her commission in negotiations if there is an unrepresented buyer, but many will not. Also, it's important to keep in mind that the listing agent would be doing the work of 2 agents if they also work with the buyer and would want to be compensated for his/her efforts. When it comes down to home inspections and repair requests, the listing agent could be more likely to negotiate those on behalf of the seller as well.
While a sellers' agent working with a buyer has to serve both sides fairly and honestly in the transaction, it would serve your interests better as a consumer to have someone who just represents your interests in the transaction and will help you navigate the process smoothly. If you decide you'd like to work with a buyer's agent, feel free to give me a call or send an email.
As far as the contingency goes (if accepted), there's no set timeframe for it...only what the sellers will entertain. Your offer is stronger if the house you're selling is already under contract before you submit a contingency offer...a little weaker if your home is listed but not under contract...and even weaker if you haven't listed your home yet and plan to after they accept the contingency offer. Basically, the home you're buying won't be listed as "under contract/pending" until the home you're selling goes under contract.
The home you want to buy is still showing up as active on searches, so it can still be shown and receive other offers. If the sellers accept your contingent offer (let's say you think the home you're selling would go under contract by March 31 and you want to close by April 30), the home stays contingent until your home goes under contract...at which point the contingency on the house you want to buy is removed. If, for some reason, your home does not go under contract by that date, then you have the right to waive the contingency and move on with the purchase of the house you want to buy or the seller can say, "No thanks...we're not waiting any longer."
Another situation that may occur is that the seller receives a better offer than yours during the time it's contingent. At that point, they'd notify you that an offer has come in and you have x amt of days (whatever was in the contract) to decide if you're going to buy the house anyway or withdraw, in which case the other person's offer would move to the primary position.
Depending on the location, price range, market activity, etc. in the area (if it's slow), the seller could agree to extend your contingency to another mutually agreed upon date. If the home is in an area and price range that tends to move quickly, then many sellers would be advised by their agents not to accept a contingency offer.
Contingencies can have a domino effect...if you can't buy, then they can't sell, and they also can't buy where they were moving...that seller can't sell because those folks couldn't buy, etc. etc. An offer is much stronger without a contingency attached, but if you do find a seller who will accept one (and there are more of them these days in the current market), then it's really best to have your current home listed and under contract before submitting the offer.
As far as using money/both sides of the commission to motivate the seller to accept a contingency, the listing agent can't ethically do that since it's "self dealing" in a sense. Of course we'd all love to earn more in a transaction; however, a my primary job as a Realtor is to put the clients' interests first.
Hope this info helps! Please feel free to contact me with any questions...thanks and have a great evening!