Where to buy penny Cryptos?

Could you elaborate on the best avenues for purchasing penny cryptocurrencies? As an investor interested in exploring this niche market, I'm curious about the reliability and accessibility of various platforms. Are there any specific exchanges that cater specifically to penny cryptos, or do I need to use larger, more established platforms? What are some key factors I should consider when choosing a platform, such as security, transaction fees, and the availability of the desired coins? Additionally, are there any risks associated with investing in penny cryptos that I should be aware of? Your insights would be greatly appreciated.