The time has come to tackle a large area of overgrown weeds in my garden. Been putting it off but must do something before they take over the entire garden! Thinking about buying some weed killer to start with and noticed online that Roundup has a cash back offer on so thought I might go for that. Has anyone used Roundup before and if so, is it any good and any helpful tips when using it. Any help would be appreciated as I have never used a weedkiller before. Thanks.