For a quick and simple purchase like that, I always just check Paybis. You can see the live price right on the page, put in exactly how much Dogecoin you want or how much you want to spend, and it walks you through paying with a card or other simple methods. The DOGE goes straight to your personal wallet address that you provide. It cuts out all the exchange complexity. Here's the link to their Dogecoin page:
https://paybis.com/pt/price/dogecoin/.