Guitar makers have advertised in music magazines such as Down Beat, Guitar Player and very many more. Some manufacturers advertised widely (Guild, Gibson, Fender) but many more didn't and adverts are few and far between. Here are some of my favourite ads out of the ones i've seen. You can browse through all the images from the category links above, or by manufacturer from the links below.
James Thompson Comment left 3rd October 2014 21:09:13 Please advise me of the value of a Harmony Marquis H570 in Factory condition.
Lisa Davis Comment left 5th December 2014 06:06:05 I have come across a guitar amp made by Sears and Roebuck & co. It is solid state, 2 channel, third channel has reverb, strength, and speed. It says 500 watt max on the max on the back.Patent # 40-14232. It has 10 or 12 inch speakers in the cabinet. It is a matching set, head and speaker cabinet. I am wondering how old it is and if it is of any value? Please respond as early as you possibly can. Thank you so much! It is also all in working order.