Cool lighter. Although often described by fleabay sellers as a ‘trench lighter’ from WWI, lighters of this type didn’t exist during the WWI period. It’s post-War and, of course, since it says “Made in Austria” in English was made for export at a time when the English-speaking nations weren’t at war with the Germanic ones.
It’s by Julius Meister & Co. (IMCO) of Vienna, and their first model was patented under the number 105107 as the “IMCO Feuerzeug” in 1920, followed by several other models based on the same patent during the early 1920s.
Fleabay will give you a steer on typical asking prices, BUT check whether they actually sold at those prices since sellers often talk up the false WWI attribution.