The cheaper versions of new spokeshaves are probably best avoided. The blade beds are sometimes not very flat or well finished, which means the tool is very prone to chatter in use. Older examples (older the better!) where better made, so are a better bet to start with. There are some very good new ones available (Veritas, Lie-Nielsen, Clifton) but the price matches the quality. You'll only have to buy one once, though.
One positive is that secondhand spokeshaves (except some of the collectable rarities) are not expensive to buy secondhand. Ebay has loads of them, or a reputable dealer (see Alf's list of dealers on her website cornishworkshop.co.uk )will sort you out a good example on request.
Sharpening a spokeshave blade can be tricky unless you use a holder of some sort. A block of wood with a sawcut in it to wedge the blade in will do - it's just to get a comfortable hold of it and keep control of bevel angle while honing.
As a 'left-field' option, the old wooden skokeshaves are an option, too. Sharpening these is a puzzle at first; setting the blade on the edge of the bench and using diamond files or slipstones, or progressively finer grades of wet-and-dry stuck to small flat sticks of wood, will get you there. Depth setting is done by tapping the horns of the cutter in and out with a small hammer - you can set a wooden spokeshave with great precision with very little practice. They're cheap, too, so getting a selection of sizes is very useful and won't break the bank. Look out for the ones that have had brass inlaid into the mouth area - they'll last longer before needing re-mouthing.
Spokeshaves can sometimes be persuaded to cut more cleanly by skewing them across the timber being worked. Useful when you get awkward grain.
Very handy tools to have on hand, spokeshaves. They come in for all sorts of shaping jobs. Building up a small selection of them would be well worthwhile, and need not break the bank either. Good luck!