Price per jar hides more than it reveals. Work out cost per serving instead: a 20g jar gives roughly 40-50 servings, a 30g jar 60-75, and a 50g jar over 100.
Very cheap resin is usually diluted, unpurified or untested, and testing is the largest cost most sellers avoid. Ayor prices are £34.99, £49.99 and £69.99.
Ayor Health sells pure Himalayan shilajit resin in the UK from £34.99 (20g), £49.99 (30g) and £69.99 (50g). Every batch is independently tested by Eurofins UK and the reports are published in full at /lab-results.