On my recent short trip to KUL, the hotel internet price was MR64 per day, while I was able to get a SIM card for my phone for RMR8.50, and 7 days internet was available for RM15.
DiGi
Where to buy
Digi do not appear to have a presence at the airport in KUL. I got a SIM card from the DiGi branded store in Sentral at the airport train station. This is a small shop by the main moving stairs (near McDonalds).
They required my passport to register the SIM. The cost was RM8.5 (about €2, US$2.50), and this had RM5 credit pre-loaded.
Where to top-up
The shop did a transfer of RM20 from a master phone to mine as part of the overall purchase. The paperwork with the phone states
Reload coupons are available at many convenient locations nationwide including dealers' outlets, selected ATMs, pharmacies, department stores, petrol stations and convenience stores. I did not need a further top-up for my trip.
Pricing
I used a short code to purchase the 7 days internet - I dialled
*116# and the RM15 was debited.
There is a daily price for broadband of RM5 (about US$1.40).
More details
here
APN
The APN was not set as standard, and I configured
diginet.
Speed/VoIP
I found the speed OK for email, but big downloads and heavy browsing was slow. DiGi allows SIP/VoIP traffic, but the bandwidth was not good enough for a call when I tried.