prices of Martin tenors seem to have gone up over the last few years and in Europe where they're less common, they can be very expensive, particularly in the bigger sax shops -
here's a Martin Indiana tenor for sale at a dealer in the Netherlands at an eye watering € 1795 -
Tenor Martin Indiana - De Saxofoonwinkel
which is about twice what it's worth
Mike Duchstein in Berlin has a Medalist and an Imperial for €1290 and €1280 -
https://www.saxophon-service.de/media/html/Instrumente/Tenorsaxophone.html
another german dealer with an Indiana at €1250 -
MARTIN Indiana Bb
all way too expensive so far...
here's an Imperial for sale in Italy for a more reasonable €700 -
carlosonny saxophone vintage
prices in the UK are somewhat less over the top, I couldn't find similar examples of the ones you've been offered, but there's a 1938 Handcraft Committee here for £1400 -
Martin Skyline Tenor saxophone | DG Music
so that's an idea of how crazy and variable sax prices can be...
since your profile says you're in Lithuania, I guess there's not an abundance of vintage american saxes to choose from and it's a choice between paying over the odds for an instrument you can actually try out or ordering one from America and paying the shipping and import taxes and hoping it's not got damaged en route.. If you're lying awake at night unable to sleep, thinking about Martin tenors, then check the Indiana over very carefully making sure that it's been well serviced, play it for about an hour making sure you can play it in tune and can blow it down to a whisper up and down the whole range of the horn and if it's really the horn for you and if you really really want it, then try to haggle the price down to €750...
I've only ever owned one Martin tenor, an early 30's Handcraft that was worn out and in need of some serious key swedging and general servicing, in spite of which it played well with a variety of mouthpieces and had a wonderful tone - the guy I sold it to said it had a fatter low end than his Mark VI.... After a little bit of haggling he got it for £400 and was likely to end up spending another £300 on getting it in full working order. While I don't miss having a tenor it was a very nice sounding instrument and it I'm ever mad enough to want to take up tenor again I'd look for a Martin Indiana to go with my Indiana alto which is still the best sax I've ever owned for my particular needs.
A Martin from 1926 is unlikely for have a front high F key, which may or may not be an issue for you, but Martins from that era are less desirable and worth less because of this and also because everyone wants the later Committee models. 1920's Martins are darker and a wee bit stuffier than later models. Intonation may not be quite as good, but that depends on the player.... as indicated above, 900 is too much.