Previously overstaying your visa in Brazil would attract a fine of R$8.50 per day which will then max out after 100 days at R$850 ( USD 200)
Currently, there's a new policy (see full policy here) on fine on visa overstay fines. Overstaying your visa in Brazil attracts a fine of R$ 100 per day which also becomes maximum after 100 days at R$ 10000 (USD 2300).
You are also banned from traveling to Brazil in the six months regardless of the number of days you overstayed ( Happened to me, I only overstayed by a few days.)
If you overstay in Brazil past the 100 days limit you also risk being deported.