You should be prepared to spend 200-300$ for decent hiking boots, especially if you are going up Kili. Sure you can get away with something "temporary" but IMO if you're guying all the way up on Kili you should NOT cut corners when it comes to footwear. There is nothing worse (except maybe falling off the cliff) than going up half way and having shoe problems, because it seriously decreases the enjoyment factor. Asolo tends to make really good boots (I have a pair that I've taken trekking to the himalayas 5 years ago, and they're still in excellent shape and in occasional use today -- see above), they're comfortable, offer excellent support (extremely important for rugged terrain, especially when you're tired from walking 6-12h a day), and the 100$ more you spend here could make the difference between a really good and really bad trip. If you're going to cut corners, do it with other things, like sunglasses. :-) -- Whatever you end up buying, make sure to not buy it on the internet and actually try yours on before you buy (a good place in MTL to check out is Sail Baron but there are probably good alternatives in CA,US), and make sure to go on short hikes with the boots for at least a month before your Kili trip to break them in good. My two cents, FWIW.

i have north face boots and love them

have NF boots and love them!

Asolo was recommended by @CraigGrocott on Twitter. These gore-tex waterproof ones are on sale for under $100 on Sierra Trading Post.