My .02 I have primed with DME. it took longer and I didn't notice a difference in taste. If you are hung up on the beer purity laws then go for it.
Also tabel sugar over corn. I don't see any difference. I believe table sugar to be ever so slightly more fermentable by weight than corn sugar and there are resources on the web to give you those numbers. I believe northern brewer has a chart on line.
one other thing;
I have a recipe that calls for 1 1/4 cup of Extra light DME for bottling after fermentation is complete. Is DME better for priming instead of priming sugar (Corn Sugar 1lb)? What is the difference in using DME or priming sugar for bottling?
unless you are doing a very large batch 1 lb of corn sugar is too much. you are generally in the 4-6 oz range for a 5 gallon batch, maybe a bit more for highly carbed beers like belgians a bit less for low carb beers like barley wines. 1 lb is going to net you bottle bombs for sure.
Yeah Purity Laws, before kegging used DME exclusively. I can't imagine the cost be a factor to a home brewer between DME, corn sugar or table sugar. Use what makes you feel good!