A word that is similar to 'duress' that captures this 'invisible pressure' that one feels

Solution 1:

As in:

When I go shopping at the local farmers market, I feel compelled to make a purchase when the hard-working farmers open up a new bag to proudly show me their wares.

compel TFD

3. To exert a strong, irresistible force on; sway:

Solution 2:

You were pressed. It expresses persuasion with lots of effort or pressure.

4a : to exert influence on : CONSTRAIN

b : to try hard to persuade : BESEECH, ENTREAT

5 : to move by means of pressure

6a : to lay stress or emphasis on

b : to insist on or request urgently

Hence:

The vendors pressed me to make a purchase.