Faab for AJ Brown

Someone dropped AJ Brown in my league. It’s a 10 team league with QB, 2RB, 3WR, Flex and TE.

How much faab should I use?

Thanks in advance.

I was thinking 21. I currently have 70 left.

Is that enough or should I do more?

At least 50, he will be a WR 1 rest of season