If you really, really want hollyhocks, they're usually grown from seed. The seed isn't hard to find -- any place that sells flower seeds will have some. After the first year (when they generally just produce leaves) they'll come up over and over and re-seed themselves elsewhere in your yard.
You can have fun selecting your own seed from hollyhocks of a particular color and, over the years, developing a collection of single-colored hollyhocks in your garden. Thomas Jefferson famously selected darker and darker flowers and ended up with a very dark purple that looks almost black -- it's still available from heirloom seed places. Without deliberate selection, they produce the mix of white-to-dark-pink flowers we're used to. Yellow is available, and so are double petal flowers.
But Kurt's right and they're a Japanese-beetle magnet. So are roses, or most roses, and most raspberries.