My preferred online hobby shops in order of dollars spent are Scale Hobbyist, Andy’s Hobby Headquarters, Amazon, eBay, Sprue Brothers, and occasionally Squadron.
For paint and other supplies, I almost exclusively use Scale Hobbyist based on price, availability, and an excellent website. However, if I were buying into a specific paint line, I would shop around for the best price, factoring in shipping and sales tax.
For Tamiya paints, Scale Hobbyist beats everyone else on price by a significant margin. The website offers excellent Notification List and Want List features.
When looking for a specific model, I often check them all. You will discover that certain sellers offer the best prices on certain brands. No one seller offers the best price on everything. Shipping and sales tax may influence best price overall.
Do not forget eBay. Chinese sellers often undercut American sellers by a significant margin.
Amazon is nuts. Prices often suck but occasionally something drops out of the blue at a crazy low price with free shipping. Amazon always charges sales tax, which sucks.
Andy’s, Sprue Brothers, and Squadron have mailing lists. Andy emails the least often. Sprue Brothers sends useful emails once a week for weekend sales and the occasional broad sale. Squadron is spammy mcspammer.
Spure Brothers offers daily Lightning Deals for 50% off manufacturers suggested retail price. There is no rhyme or reason to it. Sometimes, it’s like, :“Yay! Cheapo model!”
Andy’s has a sale section. Out of the blue, he will change it up and dump a bunch of cool models onto the sale list. Expect the list to change around or after Christmas.
Squadron has sales but they are hard to find because the website sucks. Squadron is also really high on shipping. On the other hand, sometimes, when the stars align, a really good sale will show up.
Scale Hobbyist has the best website by a gigantic margin, followed by Sprue Brothers, Andy, and Squadron. Amazon and eBay are fine for targeted searches but almost useless for category searches.
Paint is a gigantic subject. Whatever you do, be mindful of chemistry. The more you mix and match brands and types, the more variables you introduce, and that means more places where things can go wrong. For the best finishes, one must use different types of paints in the correct order.
A lot of people still prefer Tamiya paints. If you were comfortable with Tamiya 20 years ago, you should be comfortable with Tamiya now.
It may be wise to stick with Tamiya for now, testing other brands on individual projects if and until you find something better. Going cold turkey into a new paint line can be really rough.
Hobbylinc is another useful discount online hobby store, especially for science fiction stuff.
There are a bazillion smaller online hobby shops. Most have awful websites which is why they remain small.
If you start shopping outside the United States, the number of options balloons by an order of magnitude. If you go that route, ScaleMates is super useful for price checking specific models. Some foreign shops offer free shipping on large orders making them very competitive.