We reported in the beginning of April that Google was going to offer Ad credits to small and medium sized businesses to help them get through the COVID-19 lock-down.
Google updated at the end of last month some additional eligibility criteria regarding this
They are still going to release $340M in ad credits
Small & Medium business that spet in ten out of the twelve months in 2019 and in Jan and/or feb this year are eligible
The credits are going to be rolled out in phases starting in late May 2020
Google has not specified the value of the credits but did say it will vary per advertiser and will expire by the 31st Dec 2020 if not used
Full release here https://support.google.com/google-ads/answer/9803410