Dogecoin. It's popular enough and has hype (thanks to its logo and name) that can help it grow 
Its capitalization is decent and it doesn't seem to be a scam.
Are you serious about doge or you are a bag holder? No offense but i think he is asking for long term investment and not short term. I would suggest to buy it with Monero. It has a good security features and widely use now. Its capitalization is decent and it doesn't seem to be a scam.