I've seen a few TI1's (61-key and Polars) posted on Gearslutz classifieds for asking prices of $1380-2100 over the past few months, but I'm to sure if any of them sold. I would guess that they would sell on eBay for $1500-1600, if it's in good condition.
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Virus b has stayed at 700-800 for about 10 years. The ti will depreciate more but still sell higher. In the end , just sell for the value you think it s worth and wait. Just because they usually go fr A doesn't ean yours can't go for more.
Granted I've sen 3 of your eBay adds and you are terrible at selling. Maybe get a friend to help out. Some people just do the dumbest things like say obo. Always say firm because firm never means firm. But you will get rid of most of the Craigslist vultures. Show it in a clean studio environment. Talk about it like it was your kid. Never say hardly used but do comment that you hope someone finds more use for it. It's all psychological.
I could go on forever. Maybe there is a book up you can get. And when someone gives a price that is close but adjusted for standard haggling, tell them to come check it out. They have the money. They will pay the asking price nice they are in the room. And never sell if you need the money.