Homeowners insurance should cover some of the cost, even if it didn't happen at your home. Check with your insurance agent.

2nd Swing would be a good place to start. Or check your local facebook market place. See clubs for sale all the time. You may also want to go and check local pawn shops to see if anybody tried to turn in your clubs.

Most golf stores have used clubs and there's always the ole Ebay!

Sorry to hear your clubs been taken mate
I would have a look on eBay , surly you will get something back on the course

Rock Bottom Golf might be a low price option.

Having suffered the same fate myself some years ago, you have my heartfelt sympathy.
A number of us were robbed in the club car park while we were inside.
Compared to the value of the clubs, bag and stuff, I got minimal help/payout from my insurance
In the Uk if it's from your car it may be classed as "Goods in the Open" even if they are out of sight in your boot but you'd be due a payout... but it's never close to the value.
JT

This is one of my worst nightmares. Any clubs are better than no clubs, check garage sales (spring cleaning), estate sales, craigslist, facebook, etc. I've seen complete sets at garage sales for under $50.