Since cheap beer has a basic taste, it can be covered with other interesting flavors. Cocktail bitters, like Angostura or Peychaud's, are a great way of enhancing them.
Bitters are hyper-condensed flavors, so you only need a few drops to get the flavor without it being overpowering. This is a versatile additive you can experiment with.
Regarding proportions, start by adding two parts beer and one part soda and adjust as needed. Some popular choices are citrus sodas, ginger beer, Jarritos, or even Coca Cola.
Beer and lemonade together can be a delicious combination. Lemonade's lack of carbonation may soften the drink's effervescence, but it won't be that big of a deal.
There's really no limit on what beer you can use for this. Simply add equal parts beer and lemonade to your glass and enjoy this refreshing drink on a hot sunny day.