ditto to what Tartan said ... and sometimes there are demonstrations of techniques/tools at each shop.
One that I liked a few years ago featured sewing rooms at each store ... they set up a mini sewing room, to help you get some ideas as to how to organize your sewing area and things you might want to include. That's where I saw my first design wall, and knew I HAD to have one!
Some might have featured fabrics exclusive to the Shop Hop group for a limited time.
It's not uncommon that each store has a "block" like a BOM kit that they sell ... and then there;s a completion kit you can buy to put them all together.
A recent one here featured a different quilter at each store, with a display of their work.
What I like about them is that it gets me into some LQS' that I might not normally go to, and I give myself some "me-time". Again, something that many of us tend to leave out of our schedules.
When I go on a Shop Hop, I usually go with a mission ... not necessarily to purchase.
One time I did the 4-Bs ... Bindings, Borders, Battings and Backings.
At each shop I made a point of looking at these and asking specific questions, so I could learn more.
Another time, it was all about "quilting" ... when I started to do more FMQ, I realized I had not been paying attention to the actual quilting on quilts, and more so on fabric choices, placement and overall patterns and designs of quilts.
And yes, sometimes it is a purchase mission ... where my goal is to get fabrics for a specific project.
Since I started going with my personal mission ... I discovered that I was not tempted with wreckless abandon at everything I saw! You can get caught up in that oh too easily and then after the fact say, why did I buy this?
Go ... and experience!!!
You never know what might be happening in your Shop Hop!