If you already have 3/4 inch of clearance, you can buy much cheaper 1/4 inch spacers to get you out another 1/4 inch - You
might have to replace the studs in the HF hubs with longer ones to be able to run a 1/4 spacer though and that would probably get you back up near the $50
For me the fenders made the decision really easy
I wanted to run 13 or 14 inch tires on my HF trailer . . . . plus my 9 inch aluminum fenders looked terrible with the puny 12 inch HF wheels. My tires were no where near centered in the fenders I wanted to use, so adding an inch with the spacers made them look perfect . . . . and it gave me the needed clearance from the trailer wall - I only had about 1/4 without the spacers
Another thing - Shoud you one day want to run a 13 inch wheel and tire so you can go with just 25 or 30 pounds of air to get a smooth ride for your trailer, the spacers will allow that - If you tried a 13 ion there now, you'd be rubbing the sides
Check your tires, check your fenders, compare $50 to the added work of building inside fenderwells - It's almost a no-brainer
Don