Selbstlade - Is German for self loading (according to my German sister-in-law). I have also seen it listed as slide legend.
Value of ANY gun is based on the exact make, model, and condition. Unfortunately you have given us none of the 3 things we need. Selbstlade is not a brand name- it is German for "self loading". We know that you have a German .25 cal automatic pistol- but that's all. Sorry-
Without more specifics, 10-1000 USD
Well, there is a problem with your question. You see, selbstlade is not a brand name. It is German for "Self Loading". In other words, an automatic pistol. And there were several guns that COULD be yours. If you can repost with ALL of the markings on the gun, and it's condition, we may be able to give you a rough idea- but without knowing make and model, we can't.
The value of any firearm is based on the exact make, model and condition. Your Walther self loading (selbstlade) pistol has some degree of collector's value, which will be driven by condition. You will need a hands-on appraisal. Take your pistol to a local gun shop or gun show. There were at least 4 different versions made, and values are typically several hundred dollars- again, based on model and condition.
Depending on EXACTLY what you have and its condition, the range could be from a few hundred to multiple thousands of USD.
Impossible to give an accurate answer without a detailed description of ALL markings, condition, box, papers, finish, grips, grip material, barrel, sights, magazines, accessories, papers, serial number.
The Walther Selbstlade ("self-load") Pistole is known as the Model 1 since 1914 (when the Model 2 appeared). Carl and Fritz Walther began marketing the gun around 1910, a patent having been granted in 1909. It is a short-barrel automatic chambering the same 6.35 mm cartridge as the 1906 FN Browning, and of a similar design to the 1900 Steyr-Mannlicher pistol. There are 5 distinct variants made between 1910 and 1915. The age of a particular example is impossible to answer without a detailed description of ALL markings, caliber, barrel length, finish, condition, box, accessories, papers, etc.
You have a .32 caliber semi auto pistol. The Beholla pistol was developed by Becker & Hollander. In the First World War it was a secondary military arm used by the German Army. It was manufactured in Suhl Germany from 1915 until 1918, about 45,000 were produced. Value about $300 in good condition. Crown and N is the German proofmark showing it was test fired at the State testing facility.