Best “bridge” loan option under $100k?

[David S.]

We are looking to buy a new primary but want to do so without selling our current primary first. This would require an additional sum of $60-100k for 6-7 months. We have no debt but don't want to set up a HELOC or mortgage just for that sum.
What is the best product for this? Seller has opted not to do any seller financing, so that option was a dead end. 
Thanks!