yes, they are safe, legal and are worth about 70$ a bitcoin. the only way to get them is called mining bitcoins and essentually that uses your graphics card to solve equations and find blocks. it takes a wile on a really good graphics card to uncover a block. the best way to get bitcoins is to join a pool where lots of people join together to find a block. you will get less bitcoins but get them more consistently. on my 1700$ rig I get about 4-6 bitcoins a year. also amd graphics cards are best for hashing or mining bitcoins.