Sure there may be "paper" ramifications(the - I'll sue you - thing) to backing out of one deal for another, but but I have seen it happen! And if there is more money involved and the seller wants to take it.. it can happen.
When it comes to sellers.. $5,000 more is $5,000 in their pocket.. for the buyer it is another $30 spread over 30 years. Nothing is done until you sign the papers and get the keys.
Where are you in the process?
Assuming by sales agreement you are talking about a sales contract, it depends on the context in the contract. For instance, the seller can technically get out of the contract with a clause called "48 hr First Right of Refusal" (again depending on wording) but what that means is if an offer comes in higher than the current agreed agreement, the seller can ask the current buyer to meet the price of the second offer and if they don't meet the sellers higher offer, the seller can sell the property to the buyer that is willing to pay more. It is not common practice to put that wording in contracts though, unless the current buyer has a circumstance/situation/ or contingency that provokes the contracts to be drawn up that way. Hope this helps. If you are "just looking" I would be happy to help you.
Prudential Fox & Roach Realtors
In New Jersey, IF the contract is still in attorney review period, then either party (buyer or seller) can cancel the contract with no reason, and face no penalties.
If it's out of attorney review, they cannot cancel the contract for a higher offer because the initial contract is considered binding. The only option once out of attorney review is after inspection, if the parties cannot come to a meeting of the minds regarding repairs issues, the contract can be canceled.
I echo the sentiment of Ron Thomas...how would you know if there was a better offer?
It depends on where you are in the process. If you are already under contract than, no, the seller can't break the contract simply for more money. If you are still in attorney review then either party can break the contract for any reason. I hope that helps!