Buy the best equipment you can afford. If you can't afford one of the top line machines, the vintage Pfaffs and Singers are awesome - especially the ones which do a straight stitch only.
You do need a hand crank machine! In addition to being good when there's no power, they're a lot of fun to use. And very good for fiddly bits, actually. I don't do zippers often - just on a few modern skirts - but it's so easy to do them on there. Gussets too. They're almost as easy as by hand.
For my first five years of sewing, my mother lent me her sewing machine. It was a heavy, cantankerous old thing, and I was delighted when the chance arose to purchase my own. I forked over a big pile of cash for the top-of-the-range model – I was going pro, after all!
It had hundreds of stitches, fifteen different buttonholes, it could sew sideways; I’ve rarely used any of that. In fact, as Tanya and Katherine both say, you’d be surprised how useful a good old-fashioned basic machine can be – even a model that predates electricity can be a great little workhorse. You don’t need bells and whistles.
Having said that, there are also functions on my fancy new machine that I find indispensable – for me. Having used my mother’s machine for a while I recognised that there were some things about machine sewing that frustrated me, and when my dealer showed me a model with a little widget to solve my biggest machine sewing difficulty, I was delighted and bought it. So for me, that machine works.
In conclusion, we can’t tell you which machine to buy. There’s no shame in having borrowed a machine or bought something fairly humble or second hand to begin with. As you know by now, it’s helped you get used to sewing and it’s let you know whether costuming is for you.
When it comes to investing in a more permanent fixture, though, look for what YOU need. What’s useful to you, for what you make? Don’t assume that the expensive model is the best; don’t be blinded by gadgets unless you really need them. You may find, like many dedicated costumers, that you get the most joy and success from something your great-grandmother might have used.
And needless to say, take care of it. Regular servicing is a good way to ensure your machine enjoys a long and productive life, as is regular oiling. Get to know your machine, treat her well and you’ll not go far wrong.