Still need more details to give a precise answer. What make of rifle is it? Who is the manufacturer? Are you asking for the value of a Mauser rifle, or another type of rifle chambered in 7.92x57 (such as the FN49, which was manufactured during that time)?
$10 to over $1000, all things dependent. Your question is a bit vague to be answered more specifically, given that licenced and unlicenced Mauser rifles were made the world over, and their value will vary according to origin, model, rarity, time period manufactured, and overall condition.
to a fan or a collector of 8mm film maybe $15
There is a restored version for sale, so an 8mm version would have little value unless you can find someone who collects 8mm films.
100-1000 and up depending on specifics
$100-$500. You did not tell us what condition.
This 1971 world series 8mm movie, if in mint condition is worth between 10.00 and 20.00 dollars US
$150-$300, depending on condition and originality
Around anywhere from $5-$15
a couple of dollars
$15 and up
8mm tapes can only be viewed with the aid of an 8mm player. One's best bet to watch 8mm tapes in this case is to purchase another 8mm player that is not broken.
You have a rifle which fires an 8mm cartridge, and there's a number 599 on it somewhere which may or may not be a serial number. That is all that can be derived from your question - what which 8mm cartridge it fires, not who the manufacturer is, not what model of rifle it is - the things one would need to know in order to assess the value of your rifle. So, there is no way to give an answer based on the extremely sparse information you've provided.