The linear trackers from Technics overall were not that popular; certainly not when compared to their normal type turn tables with conventional swing arms. The SL-10 and Sl-15 being the two most sought after linear trackers made by Technics. If it was in mint condition AND had a new like condition original Technics cartridge - which is extreme unlikely - then it might get a good price on eBay; $200, maybe more, might be possible. But you pretty much have to have the original table AND cartridge in MINT condition(you have to have a technician inspect the needle tip with a microscope to determine stylus condition fully), as this goes best as a set - especially due to the lack of realy high quality P-Mount carts today(all the good stuff is 1/2" standard mount these days). Lacking the mint condition original cart? It's value is going to wildly fluctuate. $25? $100? Either one is possible with the lower number being more likely...
Let me ask you: does this one have all aluminum/metal body or is plastic? If it's aluminium and in excellent cosmetic condition and it works/plays -- I'll make you an offer as I want to collect some old unique late 70's-mid 80's turntables. But I'm not looking to pay much - this is just a new kind of side hobby where I want to collect some of the most notable tables from that era.
PM me.
-Chris