When and how often should I update clients?

Clients generally like up to date status, even if it's a few short sentences at the end of each work day. Perhaps you can also send a screenshot or something to illustrate what you have been doing. It depends a bit on when they expect it done.

As far as pricing it depends. You'll know you charged too little if it takes you a day and you bid $25 Generally if you don't know how to do something, it's a good idea to investigate a bit before !

But, that being said, Fix it next client!

You can always ask for bids on a web site you are doing, and compare that to see how your quotes look Keep in mind a lot of this is subjective since perception of value is everything IE if you are bidding against someone who has a large fancy portfolio generally they can ask for a bit more - but on the other hand they may be too busy to get something done quick.

It's always important to keep your client up to date with the project. The rule of thumb should be never to let your client ask you for an update. There isn't an ideal timeline for updating your clients, but you would feel the necessity of giving an update yourself. Either case, twice a week should be okay for an update.

When I get a web development project, I set up a development site on my server first thing and give the URL to my client so he or she can check it time to time to see the progress. Though, this doesn't fit all the scenarios because sometimes you don't want to share the progress with your client given it's under development and you wouldn't want to leave a sour taste in your client's mouth because the styling isn't added yet :). This works well if your client trusts you and know that you wouldn't waste their time.

As for the pricing, we never overcharge our clients. Clients are smart; they will always fear you'll overcharge them. $250 for a 6 pages site could be good depending on where you stand. E.g., you have just started out and trying to grab any project you can to build up your portfolio, or you live in a country where the dollar conversion rate is higher.

The best you can do for now to avoid being undercharged is to set an hourly rate (you'll need to do some research on that. This article can help) and whenever a project comes, roughly estimate the hours it's going to take (add a few more hours to that) and multiply by your hourly rate. You'll know (roughly) what you should charge to your client.

Regarding the SEO, I'm not sure exactly how much should you charge. SEO is not a one-time service; you can't be sure how much it's gonna take for you to bring their website #1 in the search results. SEO a progressive work, and could take months to rank a website. It's better if you do research on it depending on the niche of your client's site. However, you can make the site you develop SEO ready by optimizing it for On-page SEO. Here's a good list of things you can do on a WordPress site: https://codeable.io/wordpress-seo-tips-guide/. I also use "WordPress SEO by Yoast" plugin on the sites I develop on WordPress. You can try that out too.