Have you been shooting at a local club yet? Try to find a clay club that have a gunroom, and try stuff!
In my experience the 'first' gun fit isn't the final one, so there's really no reason to invest too much to start with... I know my 'fit' changed over the last year, and my original first gun no longer 'fits' me anymore (and I'm selling it!).
What sort of shooting do you want to do? If it's clay, you can likely find a second hand Miroku or the like -- it'll be an excellent gun for well under 1K; but there are many other options. Try to find a gun that /does/ fit you as best as you can tho:
+ Mount to the shoulder with your eyes closed
+ 'settle' it nicely to the shoulder, still eyes closed
+ Make sure your head is down on the stock -- not too much, but nicely set.
+ Remember to lean a bit forward, like 60/40 on the front foot.
+ Open your eye(s) --
You should see a little bit over the rib, and in line with the rib.
If you are 'under' the rib, the gun is not for you. If you are over but out of line left/right (significantly) the gun is not for you. If you are WAY over; same.
If you see 'flat' or reasonable amount of rib, you are nearly there...
If the rib has two 'dots' a general rule is that seeing a 'figure of eight' with the mid dot under, and the further dot over it is the 'ideal' gun sight....
Also make sure the stock isn't too short/long, and that your finger *tip* is on the trigger when you hold the gun.