It would be worth somewhere around $550
Source: Blue book of Air guns 9th edition
These are extremely valuable air rifles even in poor condition. They only made 200 that were the model 90's. It had a diopter rear sight and interchangeable front sight, The stock was made of Walnut. Please state the condition of the rifle (Is it complete? ) so I can give you an estimate of value. Rate it as poor, Fair, Good or Very Good. Falke was only in business from 1951 to 1958 in Germany.
300.00 in good condition
value depends on overall condition.
It would be worth between $80 - $100 in good condition.
about $100 in good condition
$60 to $80 in good condition. Made in three variations from 1954 to 1968
Assuming everything is in good working order it would be worth around $40 to $45
Impossible to answer without knowing who made it.
25-200 usd
Assuming you mean a TP25, about $165 in good condition.
Value in good condition is $50.00-$75.00
275-350 dollars.