You can trade with as little as 100 doge coin in exchange like Cryptopia. Tody price of Doge coin is 47 satoshi and BTC price is $7324.
So it means you can start your trading career with as little as 35 cents.
But if you want to get into trading thinking that you can make easy quick bucks , then I will say reconsider your decision.
Any way , I will suggest you too just put 1/2 of amount in trade that you can comfortably lose. The other 1/2 amount is to buy in dip , if your first 1/2 got diminished due to unforeseen market circumstances.
Actually this happened with me, I purchased Doge coin @75 satoshi with bitcoin price around $17K. Fast forward , Bitcoin price dropped to 8.5 K and doge price to 38 satoshis. You can see how easily the original investment become 1/4 of its original value. That's why I suggest to keep other half in reserve so that you are able to purchase in this bearish market to minimize the loss.