What i can use for tier 1 link ?

Hello, I apologize if my question is newbie, but I would like to know what type of link I can use for tier 1 for my money site. Guest posts or a PBN is good for tier 1 ? And Free guest posts should be avoided due to their spammy content , right ? thanks in advance !!!

Every type of links can be used for your tier 1,
It's more about the quality of the links instead of the type itself,
You can find spammy pbns, guest posts, web 2.0s, comments, etc... as well as quality ones,

A big red flag for spammy links is the cheap price, no one going to really sell a solid link for a couple of cents, in most cases at least,
Yet, not every expensive link will be clean & good enough,
You'll have to check stuff manually & have enough experience/common sense to spot the difference

Quality matters, you can create any type of links to boost your tier 1.

I'd recommend a mix of high-quality guest posts and PBNs, but with caution.

stay away from crappy porn links

Non hit sites from GOOGLE with good content would be ideal for external link of your website.