Why the difference?
In my flashcard set Cashier), I make two similar statements:
Buy one, get one half price. Buy one, get one free.
Why are there two different ways to say it?
Compre uno y reciba uno a mitad de precio. Compre uno y llévese otro gratis.
reciba o llévese
"reciba" is easier to say 
Remember: I am a "way beginner"! 
3 Answers
Hello Sylvia and Welcome to the SpanishDict forum 
In Spanish, like in English, there are often at least two ways of saying the same thing
eg 1 ¿Me puedes ayudar? = Can you help me?
2 Puedes ayudarme? = Can you help me?
With regard to your specific question they don't mean exactly the same as you can see from the translation
Compre uno y reciba uno a mitad de precio. = Buy one and receive one (at) half price
Compre uno y llévese otro gratis.= Buy one and get one free
With great respect Sylvia, why should it be so surprising that Spanish has two or more ways of expressing the same thing? English has many other examples of using different ways to express the same thing 
eg 1 What time will you get here?
2 What time will you arrive?
3 What time will you be here?
I hope this helps you
Sylvia, welcome to the forum. As another beginner I can tell you this is just the tip of the iceberg. You're going to find a lot of things that don't make sense so you will just have to trust those who give you good advise and answers like the one Feliz just gave. Bye the way, interesting avatar, I've never noticed the resemblence of a 58 (or thereabouts)Caddy tailight to a face before, ¡qué padre!
Language = ways to express yourself It all about what will you create using words to express yourself
