Check ebay for RAM. Search for 'SRAM' or 'static ram'. I recently picked up 50 pcs of 256k 70ns for 3UKP. (about $6). Also choose 'worldwide' for location, otherwise you'll just get results from your country, or whatever ebay site you started on.
If you can't get 8k ram, then get 16, or 32k...you don't have to use all the memory, just tie the higher address bits to GND.
In fact, most ebay shops will happily ship to india, and some are very cheap. I wouldn't be surprised if you could get all those parts in one shop for under $20 (US).
Also, I know you probably don't need the fastest oscilloscope, but I would recommend an external parallel ADC. This could be connected directly to the data I/O of the ram, so sampling speed would only be limited by the ADC and the speed at which the PIC can increment the ram address. I'm sure 1MSps would be achievable.
Blueteeth