How much is this violin worth? (Scherl & Roth 1980's Stradivarius)?

Sorry, not enough information. There should also be a model number, the serial number is useless. There should be a number like R301 or 301C, that will help determine the value. However, even with that, the condition will be very important including the maintenance condition. Strings that are a year old should be replaced, the hair on the bow needs to be fresh, what's the condition of the bridge. These things need to be new to not detract from the value. Some S&R violins from the 1980's that are Stradivari copies can be worth $1000, others only $150. The best way to determine the value is to have it appraised at a violin shop, all other values will be speculation since it hasn't been seen in person.

First of all, you do know that a modern violin (I know if you are very young, the "1980s" might seem "antique" to you) MODEDLED after Stradivarius violins, isn't the same as having a real Strad. It is more likely have been made in Cleveland rather than Germany, because just doing a brief Internet search, the violin maker opened up an American shop there. Even in Germany, they apparently made violins to sell to visiting Americans. Go figure.

NEW violins seem to be sold in the range of $299 to $400, the going rate for the very basic of playable student quality violins (and they still can differ greatly in quality, depending who actually made the thing). If your violin has condition issues, that can affect the value if the condition goes beyond just looking a bit "used". You need to take it to a luthier or some place where you can get an expert to look at it and appraise it. A real violin appraiser charges for his assessment, but maybe the local violin shop will at least have a look at it and tell you if it is in playing condition, or can be made so, and what you can REASONABLY expect for a used student violin.

Scherl Roth Violin

Not a lot, maybe a couple of hundred bucks. These aren't rubbish by any means, but they are definitely student violins that probably sold for a couple of hundred when new. You say it's a little beat up, which will definitely lower its value.