have you tried the nature babycare ones, they smell less chemically than others, but are expensive. you can get them at boots. reusables are fab but expensive initially, have you thought about buying a few second hand? here.
I used the nature baby care ones and didn't find they leaked. Also used Moltex Oko, which you can get in some chemists, and online. They are more expensive; ethical superstore is the cheapest place to buy.
It might e worth contacting Surestart. If you're lucky and live in the right area they do a reusable nappy hire service for a £5 refundable deposit. Also National Childbirth Trust nearly new sales, and even ebay are good if you don't mind buying secondhand. I have heard cloth nappies are good pre-toilet training as the child gets used to the 'wet' feeling.
I used Moltex when my ds developed a reaction to other mainstream dispo nappies and found them very good - they were worth paying the extra money for.
However I did use reusables as well. You can always find some very good deals on the internet. Once my ds was 2 we were using a mix of Motherease sandy's and Fuzzi Bunz which I stuffed with terry nappies and prefolds. I only had 4 Fuzzis. They dried really quickly so I just washed them every night (had loads more stuffing though).
How I looked at it was that I was spending at least £20 a month on dispos so in 3 months the reusables had paid for themselves. FWIW my DS potty trained at 2.4, but we then used the nappies for a few more months at night.
I have kept the nappies for my next ds, but you could always look on it that ou can recoup some money on reusables if you sell them once you are finished with them.
Mamadiva, don't think that your ds is late potty training. My dd was in reusables from 8w and didn't come out of nappies until 3y4m when she just decided she didn't need them any more. 2 days later she was reliably dry and never used a potty at all.