Budget lens for Full Frame camera

[Dave64]

I have recently started using a Canon 5D Mark ii full frame camera, and am looking for a budget lens to replace the Tamron AF 18-200mm that I used on my crop frame 60D.

I carry my camera with me a lot, and liked the Tamron as it did quite a good job for most circumstances.
I know it was a budget lens but I was quite happy with it until I could afford a better lens.

Can anyone suggest an alternative 'all-in-one' type lens that I can use with my full frame camera.

I will be looking to by a used lens as I don't have a big budget. so it will be a stop gap lens until I can afford to upgrade. 

I do have a Canon EF 28-80mm lens that I am using at present, so I would consider something that would accompany this, but ideally I would like one lens to use whilst wandering around.

Any help would be much appreciated, Dave

[ebiggs1]

Dave,

Avoid primes at this time.  They are specialized lenses and therefore you need to have a specialized need for one.  Until then stick with zoom lenses.  In the past, very much so past, primes were the way to go if you wanted great IQ.  However, now zooms offer the same or almost the same IQ and the added benefit of multiple range FL.

[ebiggs1]

"I do have a Canon EF 28-80mm lens that I am using at present ..."

There were several version of the 28-80mm?  Which one do you have?  EF 28–80mm f/3.5–5.6 another was the EF 28–80mm f/2.8–4L.  I am guessing you have the first one mentioned?  If that is correct you already have a cheap lens why in the world do you want to replace it with another cheap lens?  Use what you have until you can afford something better.  If on the other hand you have the latter, it is a good lens.  No urgent need to replace it.