In the past, you used to be able to top up your TnG card at manned booths. Not anymore, a lot the manned booths don’t perform topping up anymore. Instead you could do topping up at petrol stations, convenience stores and various other shops. The complete list of topping up with and without fee is provided on PLUS’s website. The fee is 50 sen per RM20 or RM50 top up.
I think a lot of people like to ask if they could top up their card using the TnG eWallet. Basically you cannot, the TnG and the eWallet are like two separate systems. So it’s quite a hassle sometimes having to make a specific trip just to top up the TnG card. For the eWallet though, you can top up with Debit/Credit card within the App. Update: they have launched the NFC TnG card which allows topping up the TnG card via eWallet. Very hard to get hold of the card though, hoarders snap up all the supply and sell them for 5X the cost of the card.
For those embarking on a trip from JB to Malacca or KL, you need to pay RM20+ and RM30+ of toll respectively, and oftentimes your TnG card will be short of that amount. Here’s a convenient way to top up your card along the north-south highway: Self-Service Kiosks (SSK). There is no top up fee, and you can pay with your eWallet balance (which you can easily top up anytime). The kiosk generates a QR code and you just need to scan it with the TnG app to make payment. Update: unfortunately, they removed this feature of topping up with eWallet and it’s cash only
For those traveling north-bound from JB, the Kempas Toll Plaza SSK is especially convenient. It is near the toilet of the R&R area on the left right after passing through the toll booths. If you plan to do top up, do use one of the two leftmost lanes when going through the toll booths so you can turn into the R&R area.