If you are looking for a cheap lavalier microphone to have better sound at video conferences or to get started with YouTube I can recommend the BOYA BY-M1. It provides really good value for money and can usually be found for around 20 Euros (25 US Dollars) online. I got mine from Amazon (affiliate link to amazon.com / amazon.de) for about 18 Euros.

One differentiator compared to other similar microphones that are often advertised specifically for use with smartphones, is that the BY-M1 can also be used with devices that do not provide power. Smartphones and modern laptops usually do this, but professional audio equipment (e.g. dedicated audio recorders) only provides 48 V phantom power and will therefore not work with a typical smartphone microphone. For those cases the BY-M1 comes with a small battery (LR44) and also a 1/4″ TRS adapter.

If you use a different microphone I would be interested to hear about your experience in the comments.