That's a standard post-WW1 "alphabet" commercial Luger in 7.65x21mm chambering. This is the most commonly encountered model of all Lugers ever made. The alphabet serial numbered commercial Lugers began production in 1921 and started with either serial number 1i or 2000i depending upon which theory you accept as true. Your Luger has an o suffix letter and based on that I'd guess it was made in 1924.
Even in excellent condition, the alphabet Lugers have little collector interest and do not command a premium. That's partly because of their commonality and partly because .30 Luger cartridges are sometime difficult to find and expensive. They are top quality pistols that shoot well and are accurate. The "GERMANY" stamp shows that it was manufactured for export to the US.
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