Is it expected that an amateur would compensate their trainer for assessing horse sale ads/videos for potential purchases? I know that if you hire them to source for you, they should be paid ~10% commission (which I assume means they try them for you and/or come with you to try them), but what about horses that you find on your own and/or plan on buying sight-unseen based off video and vetting? If so, what is a fair amount to compensate them for each horse listing you send them to review?
It is a matter of negotiation.
there might be a flat fee, a per hour rate.
Make sure to talk with your trainer and clear the expectations on both sides, and put it in writing.
Discuss with trainer. I would expect to pay something for this, but not as much as for a search where trainer is fully involved in everything. They may already have a standard fee for things like this, or you may need to reach an agreement. Make sure there are no surprises - like they stick their hand out for 10% when the trailer rolls in with your horse. Of course, make sure trainer will be willing to work with a horse purchased in this way. Some can be strange like that.
I always paid my trainers to evaluate videos and to come with me when I tried horses. They did not take a commission based on the sales price. We negotiated up front how much they wanted to be paid. This way their compensation was not linked to the purchase of a specific horse.
You’re taking up a professional’s time with a professional matter - you need to pay something for that! In my experience paying your trainer’s hourly rate has been appropriate but it will depend on how they structure their pricing and possibly an inconvenience factor too - reviewing videos is likely to be extra work after a long working day and not something that can be worked in to their usual hours.
Yes. If you want to pay anything other than the trainer’s published commission rate, you need to discuss it before you start the shopping process.