Kindly advise on the best course of action in this scenario. Just received a notification stating that an offer of $100 has been made on the domain name at Sedo. Meanwhile, the asking price is set at $433.

 Considering Sedo's high commission rate, selling for $100 would not be wise. Is it possible to send it to auction or make a counteroffer of $433? Alternatively, should the asking price be removed to increase counteroffers? Thank you for your input.

P.S. The domain is a three-character .info zone.

The probability of bids coming in during an auction is uncertain, making it a gamble. Although, Germans tend to value .info domains.
 It's better to propose a reasonable counteroffer, say around $350, and negotiate with the buyer to determine their maximum budget before deciding whether to send it to auction or sell immediately to avoid prolonged waiting.

If I were you, I'd stick with the $433 price tag. If the buyer is interested in the domain, he will buy for this price as well.