As ChazzMcKlausna said we need pics or at least more information. The Turks updated many different models of Mauser rifles in the 1930's and 1940's. Thus the value of yours will depend upon exactly what model it is and the condition it is in.
Here is a website that will help you identify which model you have:
It definately depends on condition and locality. Cosmo'd and "NRA good" condition M38 Turk Mausers run about $135-220 in gunshops here in AK.
However I've bought them online in the last two years for as little as $70 (+ shipping) off the Trader. But- them one has to factor in shipping.....
Rifles generally cost 30-45 bucks to ship to Alaska. That is a fact of locality...
That being said, it would be VERY difficult to find a Turk Mauser here in a gunshop for less than $135.....and as mentioned above, most would hover in the $200 range.
Recently, I see an upword trend in pricing. So... over the last two years I've paid as little as $70 (before shipping), to as much as $175-- the deciding factor for me was the condition. I now have Four Turk M38s, and one M38/46 short rifle. II paid $175 for the short rifle).
BTW.. the $135 rifle was in excellent condition.... although externally it looked gnarly before I cleaned it. I know it was I above average condition when I saw picked it up from a local shop, but after cleaning.. WOW.... Like new bore, not even a dent in the stock.... great bluing.... Decent find!
By the way.. clean em up, smooth the triggers a bit or drop in and aftermarket trigger, add a set of Mojo snap sights, and you have a damned fine inexpensive Milsurp ammo burner to plink or hunt with. My M38's Turks will shoot 1.5 -2 MOA with Yugo M75 Sniper ammo all day long........ (AND .75 -1.5 if you glass bed the actions-- and SOME M38's are pillar bedded from the arsenal!).....
(My Turk SHort rifle remains untouched..... it's much less common than the M38's)
Considering how many were actually made (in comparison to mosins and k98 mausers) value may go way up. Add in future import bans and the fact that jap. rifles used to be $20, who knows? At the peak of importationd, prices were way less than $10 each. Still have the invoices