there a many Dex Exchanges which run on Ethereum blockchain, i am not so advanced in my knowledge about crypto currencys, but i ask myself one thing, it is possible to use a API or something simular with which you can read the current price for any token/coin at any Dex Exchange?
As far as I know theres no dex exchanges or AMM that offering an API for such function, but most of them display their native token in the bottom
Do you just want to see the price of certain tokens in fiat/dollar? In that case then just pair it with stablecoins (USDT or USDC) or you have an option to check them through market cap sites such as CMC or coingecko.
Or does every Dex Exchange which run on the Ethereum blockchain have the same price for every token/coin?
Of course not, it's different for each token