Parts are more difficult to find that your average Toyota or honda, but they are available. You have to search around more and they may be priced higher than others.
You must remember, it is a 26 year old vehicle. So keep this in mind. Things will break. Be ready to spend 1-3 lakh above the purchase price for maintenance that may be needed and not disclosed by the seller. Watch for reversed meters. If you are not technically inclined, please ensure you know a good mechanic. And by good, I mean not a desi ustaad.
They are good vehicles, but please ensure you find a good and well maintained example. Or, please have it inspected by a competent mechanic before buying.
Have a visit to the pajero club post on this website. There's a high number of posts there, some of which may help.
You may also consider Hilux surf. May find a nice on in this budget too.