I would go with a new plane if you can.
If your going to start with one plane, I would not get a smoothing plane. I would suggest a #5 or 6 as your first. A quality plane sharpened correctly and mouth closed down will give excellent results.
As you've read, If you don't mind spending several hours refurbishing, you can pick up an old stanley on EBay for $50 or so. Down side is you could have a plane with bad parts. If you upgrade the blade add another $70 at least. Bottom line, unless you find a flea market deal (never seen one yet), you can figure on having at least $100 invested with a blade upgrade. That doesn't include possibly hours of work flattening the sole and frog and repairs.
I recently bought a WoodRiver #6 when it was on sale for less than $150. I am very happy with it. Took a little work to flatten an hone the blade, though, but properly adjusted, I get a surface equal to my smoother.
You can tell the difference in quality tools, so don't go cheap if you can afford not to. IMO and experience is the time spent refurbishing and upgrading blades aren't worth it in the end.
I've learned its best to start with the best you can and don't limit yourself with a mediocre quality tool. I've made the mistake is getting an inferior tool and believing my skill level was low when actually it was the tool not working well. I recently experienced this with a Stanley plane. No matter what I did, I just could not get the tool to either stay adjusted or work to my standards. In the end, I think the frog bad, but I spend over 20 hours trying to get it to work. On the other hand I I have a very nice Record #4 with Veritas blade that is pretty nice, but the plane was pristine when I bought it
No to belabor it, but I will never refurbish another plane, so be careful before you venture forth.
For my money, check out WoodRiver.
Skip the smoother for now and go for a#6. You will have a little jointer ability as well as a shooting plane.