Thank you for submitting your item for appraisal. The Frank Holton company was a large brass instruments manufacturer in Elkhorn, Wisconsin with hundreds of factory workers. Frank Holton bugles are rarely offered at auction.
In general the demand for bugles is limited and prices are low as a result.
The bugle in your possession is in good condition except for the one dent, which might be removable with a small steel ball and a super magnet and some heat.
The estimate is based on similar bugles offered or sold at auction.