Besides creating high-quality content, there’s very little that you can do on your page to make other sites link to yours. But you can run campaigns (e.g. guest blog posts or press releases), and these are considered to be Off-Page SEO. Please be careful with this as search engines don’t like every ‘technique’ that exists, especially if they’re dubious (e.g. buying backlinks). Read this Moz article if you’re looking for more information in this field.
Accept online payments/set up an online store: On some builders like SITE123 and Strikingly, you can create an online store on the free plan, and sell one or two items, but to sell any more you have to upgrade. On some you can create a store, but you must be on a paid plan to actually accept payments through your website, (like Wix). Others won’t let you create a store at all unless you’re paying, such as Weebly. So it varies, but one thing remains the same: in order to have a successful and scalable online store you will need to upgrade to a paid plan sooner or later. Once you’re on a paid plan you can unlock features such as connecting different payment types, (for example PayPal, credit/debit cards etc), get rid of transaction fees, track and manage your inventory, and more!
OBSERVATION – You can have the content and the links – but if your site falls short on even a single user satisfaction signal (even if it is picked up by the algorithm, and not a human reviewer) then your rankings for particular terms could collapse – OR – rankings can be held back – IF Google thinks your organisation, with its resources, or ‘reputation, should be delivering a better user experience to users.