Looking at your specs, I think $350 might actually be a bit low for what you've got. Your Legion 5 with the Ryzen 7 5800H, 16GB RAM, and 512GB SSD is still a solid machine, even with the RTX 3050Ti.
I've been browsing the used market lately and seeing some interesting pricing. On eBay, I spotted a Legion 5 with an RTX 3060 (which is definitely better than your 3050Ti) selling for around £550 ($680-ish USD). On Reddit, people were mentioning Legion 5 Pros with 3060s going for around $800 on Facebook Marketplace.
That said, the RTX 3050Ti is definitely the weak point here - it's quite a bit less powerful than even the 3060, and for serious gaming, most people recommend at least a 3060 these days. But your other specs are still very respectable.
Given the current used market, I'd probably start around $450-500 and see what kind of interest you get. You can always come down if needed, but $350 feels like you're leaving money on the table. The 5800H is still a capable processor and 16GB RAM + 512GB SSD is a nice setup.