Jan 02 - Describing a store to a person in Spanish

Hello there,
I had a recent run - in with a Spanish person who was asking about a store and their prices, and I ran into some grammatical errors when attempting to describe which one is cheap.

The person asked me 'Which store do you go to', so I said 'Visito almacenes que ofrecen descuentos a mitad de precio, así son muy baratos'. Now, I'm still uncertain whether the ending there - so they are very cheap - was correct.

My question is, which is correct? The one above OR saying 'así que son muy baratos' to say '... so they are very cheap'? Or if it would be helpful, is there an even better way of saying it?

Thanks!