$700. was probably close to the price when new and a whole bunch of people thought it was worth it. They were spending dollars that were worth at least seven times what a dollar is worth now so if it is in good shape and can be returned to new condition appearance easily then you'd have what tons of people bought for $700. for $100. of their time's dollars.
If you want to see it in your terms multiplying their dollars by the same likely innaccurate factor. That way they paid $4900. for what you could have for $700.
Is one weird way to look at it, rationalize it, and BUY it.