Yo ucan buy panties for boys. You can acually by thongs for men!!
Thet are called “manties” but why not just wear regular panties as they are more comfortable, if you are a younger boy just think about all the teasing you will face when friends find out not to mention facing your parents, maybe wait awhile and if you still want to wear panties make sure you get the right size as male sizes are different to female for obvious reasons, i prefer full briefs or hi cuts myself but you could try a few styles and see what you prefer
Yes you can. They can be found in the women’s and girl’s clothing sections in any department store. Don’t worry, panties aren’t prejudiced. They don’t care whether you’re a boy or girl.