nginx and varnish on a 1Gb linode ??

Hello,

I run a webserver with nginx and php-fpm on a 1Gb linode, I use php opcache.

I was wondering if I should also use varnish.

I read online that it can be a better choice to use nginx only because it can also does what varnish does, varnish is also memory consuming (consiering 1Gb linode).

What do you think ? is that right?

Do you think that using varnish in front of nginx is a waste of time/memory?

thank you