Don't buy lots!
Aldi are generally widely rebound for being good and cheap, but to be honest, you'll want to try out several when your baby arrives, as they may be skinny or chunky or have crazy legs (like mine did!), and nappies fit differently, so you'll kick yourself if you waste money on ones you won't use.
Buy a couple of packs, but there are usually deals on at one supermarket or other, so you can still get good deals later. Maybe if you want to spread the cost, put some money aside each week from now that you can use for nappies later?
Wipes... I liked to use water wipes for the first six months, just because it is less...chemically. But after that I use any :) (though I do like the Pampers sensitive ones...bit pricier though).
Oh, and on pampers - I like pampers nappies for night time as they are much more absorbent, but I use cheaper ones or cloth ones during the day, so it's only one pamper per day, so it's not quite as expensive!
Congratulations, and enjoy the nappy experimenting when your baby arrives :)