If you're really serious about brewing, indoors, and doing 5 gallon batches regularly, a 240V, 3500 Watt countertop induction plate (i.e., Avantco IC3500, <$200) and a suitable 10 gallon kettle ($50-200) will do it. The move from extract to all grain would be easy and fairly painless.
But it's a $300-500 outlay together. And you need access to a 240V socket, 20A or higher, such as an existing 30A clothes dryer one.
Unless you can put one of those in yourself or jimmyrig one that's safe to use, easily adds another $300-500 or more, becoming cost prohibitive quickly.
A ready to use single burner, 120V 1800W induction plate (and a suitable kettle) can be used in a jiffy, and plugs into any 20A (kitchen) outlet. However, expect boils to be slower as the volume increases. Using a 1000-1500W heat stick could boost that quickly if needed.
2.5 gallon (partial) boils are very doable on such a plate using extracts or smaller partial mash batches. But for many very hoppy beers as well as any all grain you need full volume boils. You could do full extract boils and even all grain if you stick with smaller 2.5 gallon batches. That gives you more variety too. Brew 2 batches back to back (only one prep and cleanup) if you need more beer.
