It all entirely depends on the weight and quality of the harvest. In Texas (I’m from Texas) the current going rate for 1/8 ounce is anywhere from $40-$60 depending on quality. So your usual math, minus the fact that people expect to get a discount the more they buy, and you’ll be able to get a rough estimate on how much is blackmarket worth is.
Then you would need to do some crazy research and find out what blackmarket prices were in places like Colorado before legalization, and their current prices including all applicable taxes. From there you should be able to work out what you can expect from a potentially legal market in The Lone Star State.
Hope I was able to help and not ramble too much