What is the best way to buy DEC or SPS using fiat?

With SPS and DEC being so low, I am currently looking for the best way to use FIAT to buy both, what methods would you all recommend?

There are so many exchanges and different ways to purchase SPS, I have a coinbase and metamask wallet. Last time I tried to use coinbase to do this I ended up losing alot to fees and and I know there has to be a better way. I need those more crypto savvy to help me and others buy this dip.