https://baremetrics.com/pricing or rather it offers too many features I don't use. https://mrr.io/ is a cheaper alternative, profitwell is cost-free, so competing just by price is probably not a good idea.
Ahrefs. It's a very cool SEO tool, but expensive for me. I run a startup Top Software & Tools for Business https://a2is.com/ and pay $ 180 monthly.
Hubspot. I find it surprising there is no good competitor that does all in one marketing like hubspot but at a more reasonable price friendlier to startups. Heck, I might build one.
Intercom. Their pricing is basically based on how many people you show the widget to and not how many people actually send you a message. Made it unusable for us.