The first under-$100 true wireless earbuds from Beats (and, by extension, Apple) are here. Starting today, you can order the $79.99 Solo Buds online in four different colors — black, purple, red, and gray — and they’ll be in stores on June 20th. The red earbuds come with one advantage over the others: they include a translucent case that’s reminiscent of the one that comes with the Studio Buds Plus. The earbuds themselves are opaque, but it’s still a great look. I’ve been testing…