100$ of deposit is definitely not enough for crypto arbitrage.
First of all, you gonna need to buy the access for a decent arbitrage bot because beside the price difference you also need to know the market depth just to know the amount or coins you can buy. It is hard to do this completely manually since the arbitrage situation can last only for 15-20 minutes.
You need to have enough deposit to cover the exchange withdrawal fees. With 100$ deposit these fees will kill the entire profit.
And of course a decent arbitrage bot can easily cost over 1000$ for monthly subscription.
This is probably the best answer to everything the OP wrote. $100 for Arbitrage trading is not even enough to cover the fee without losses. Even if an unplanned jam occurs on the network, loss is almost guaranteed.
_Manually monitor cryptocurrency price on different exchange.
I believe this is just a joke. Has anyone tried to do this manually?