Coinbase only recently stopped accepting credit cards for transactions. Too many legalities. But there are several very trusted sites that you can use to buy BTC with a credit card. Localbitcoin is a reputable site that allows credit card transactions. You could also use Cash App. That's probably the most trusted these days. Good luck!
Although Ethereum isn't worth as much as a Bitcoin, Ethereum is still worth a pretty penny. There are still many people who use it so it's still in heavy circulation. But again, not as much as Bitcoin. I would say it's worth accepting ETH payments but maybe wait till the market is more stable to invest in it.
Google is your friend! You can find almost anything on there. Use your imagination. For instance, what I do is go to Google and search for "trial instagram followers". Your results will be a bunch of social media marketing sites who offer Instagram followers offering free trial runs of their services. It's very handy for getting some free Instagram followers. You probably won't get the thousands you're looking for though unless you visit pages and pages worth of sites and that could take days.