They are only worth what someone will pay for them. Looking at prices online can be misleading because just because someone is asking a certain price does not mean they will get it. It also may lead to disapointment if you cannot find someone who will pay what you want for them.
Your best bet would be to put them on Ebay and see what you can get. I looked around a bit and I think 150 is probably pretty accuate maybe more if they are in mint condition but you would most likely need to find a collector to get that price because there are a lot of great iron sets you can get for around $200.00 that are newer and more playable IMO. You could also try the marketplace on TST since it is full of avid players and knowledgeable buyers who would be willing to pay fair price for a classic set of clubs. Good luck.