The word has a couple of meanings depending on the context in which it is used:

1.  To go on a grocery run for fresh produce.

“Babe, I feel like making banana bread today, could you make a freshstop after work?”

2. To make a stop for refreshments on your travels.

“Everyone use the loo, we are only making one freshstop in Bloem this time!”

The usage of this word in this way is believed to have been derived from FreshStop at Caltex