If they sat there for 5 years without being sold, then I imagine they weren't very good coins, or the price just wasn't right. Don't fret over it, those coins will always pop up somewhere else. I imagine he was raising the price so that next time someone shows interest they will make an offer, which will bring the sale price back to what he's been asking for them over the last 5 years.
If these are silver or gold coins he may have adjusted the prices due to PM value. But otherwise he may have raised it because you showed interest in it. The seller is thinking, since you're interested lets see if you're willing to pay the extra amount.
Without knowing the coins, it's really hard to say what the dealer's motivation is. But I will say this; There a good number of coins for sale to the number of buyers. Collectibles are taking a hit, coins included on this economy. Just look at the Redbook prices for the last 4-5 consecutive years and look at the eBay completed listings ! Man, I am not selling anything, and buying what I want after a lot of research. Your coin is out there someplace at the right price. You just have to shop a bit. I wouldn;t let any dealer hold me up. Businesses need to sell to make overhead costs. No buyer NEEDS to purchase. As said, you can find what you WANT at a good number by looking around. IMHO gary
Look else where. Probably worked out for the best since you were slightly on the fence anyways. Looks like he was trying to pull one over on you.
If the seller raised the prices due to increases in PM values, fine. But if you're looking at base metal coins, I'd avoid making a purchase from this dealer. With the worldwide internet dealers, he should be concerned about competition from anywhere on this planet.