Visited yesterday without charging.
The chargers are the first parking spots at the bottom of the entrance ramp.
The setup is still the same as I've seen in other online pictures previously. This confirms the chargers are the Mobilecharge chargers visible on IchTankeStrom.
It's really not easy to find out the price of this parking. The official website for the venue seems to be https://www.aha.ag/ but they don't mention their parking anywhere. Even on location, I didn't see the prices posted on the payment machine. The only place I saw the price was on the ticket dispenser at the gate. It says 1.50CHF/h anytime.
I don't think the payment machine I used accepted credit cards. Not sure if other machines do.
There are other private chargers in the rented area of the parking.
On GoingElectric the charger seems to be documented correctly in picture and description, but it's named and placed above the Gais Center, which I can confirm is wrong. The chargers pictured are indeed in Aeschbachhalle which is a completely separate parking https://www.goingelectric.de/stromtankstellen/Schweiz/Aarau/Gais-Center-Industriestrasse-20/35481/