Do I need to replace all my struts if I just need the front end struts replaced?

What is your question?

I called for a quote on replacing my struts and this is the cheapest place where I can do that. Other places will charge me over a grand and its just $600 here for front and back struts. The man said I need to replace the front end as well as the back end if I replace my struts but its only the front that needs replacing. My car is kinda old and I'm tight on cash so does anyone know if I should replace both ends even if its just the front end struts?