Is there a going price list?

I am trying to sell a lot of my stuffs in DS. I posted on the store forum but have not had much interest. My guess is my prices are too high and want to lower it down to sell. Is there a guide somewhere on this site to help with pricing of items/monsters on DS?

There really isn't a going price list as the market fluxuates so much. During events, EP are so hard to come by as people are spending ~200 EP to get into the top 100. The best thing to do is just go by people's shops and what you've seen or traded for in the past.
you can always ask people on the forum too, there are many older players who will know the general price range. You might have more luck trading monster for monster though, as EP are hard to come by and you will often get less than a card is 'worth' if you trade for pure EP.
As for a general rule, most A monsters below 16BP are worth less than 1 EP each unless maxed or part of a popular combo - Wyrms, Tyranny Brutes, Sin Demon. Most of your 16-19 BP monsters are worth less than 5EP each, and 20+ BP are 5+ EP each depending on rarity, skill and popularity. For example, Simian Lord Hanuman is generally worth 10-20 EP per A depending on the market and your buyer whereas Lab Mino is considered less valuable.
I know this is kind of a frustrating answer, but the market is quite fluid so prices change constantly. Hope this helps out a bit though!

TLDR: Always changing, ask in chat or forum for current opinion