Hi, very interesting topic.
I confess. When I first started running I went to my local running shop and had a gait analysis done. It was not a video one but I ran on the treadmill while they watched from behind. Then they let me run around the shop in different pairs to see which ones I preferred.
However, it wasn't until I had chosen that I found out the price. I was expecting them to be about £40 - £50 as that is a bit more than I would normally pay for a street pair of trainers.
When they said they were £85 I realised that I could not warrant paying that much. Especially as I had just started running and didn't know if I would continue running or if it was just a passing phase (mid life crisis?).
Anyway I took a note of the model and managed to get some of the previous years model for £40 online. I did feel guilty but that was quite a difference in price.
I have since been back to the shop and purchased several items. I also recently bought another pair of trainers which were in the sale at £65 so I don't feel so guilty now.
I also had a proper video gait analysis done this year at the FLM Expo. This was performed by trained Asics staff.
So in answer to your question I think that I would want to know that the person in the shop had proper training before spending money on an analysis. I would then want the price to be taken off the shoes if I bought a pair. However, I would probably still weigh up the cost of the gait analysis at the shop + buying online against buying in the shop.