Hi,
There is no charge to increase your quota limit for a VM size. You only pay when you actually use it. For example, if you increase your limit for "Standard NCADS_A100_v4 Family vCPUs" to 10 and the increase is approved, there will not be any charges until you have running VM(s) using that VM size family.
Please click Accept Answer if the above was useful. If something is unclear, please add a comment.
Thanks.
-TP