Bicycle Mechanics - Swapping out handlebars with bar end shifters

I am considering purchasing a road bike with bar end shifters and I want to replace them and the road bike style handle bars with a set of straight handlebars.
I am a novice mechanic at best so aside from the obvious issue with the brake levers needing to be replaced, how difficult is it to replace the bar end shifters with say a trigger shift setup?
If I decide to take it to a shop (I know prices would vary) but how much could I expect to pay to have this done? Also, should I keep the bar end shifter / brake lever components? Are they difficult to come by ie: worth anything?

The bike in question is an 18 speed Fuji America.

Thanks!!

SS

It might actually be cheaper for you to buy a set of Paul Thumbies (http://www.paulcomp.com/mtthumbie.html) than the appropriate shifters, depending on your exact set up. You would re-use the bar end shift lever itself, but not the mount that places them in the bar end.

Or you could always use a pair of cheap thumb shifters, Sunrace (http://www.sunrace.com/en/products/detail/m05?sku=SLM10) makes one that retails for about $10, it's a great choice if you don't mind friction shifting, but they aren't as cool as the Paul Thumbies.

Wait...18 speeds, meaning a triple with a 6 speed cassette, or a double with a 9 speed cassette, because that makes a big difference. If you have a 6 speed cassette, indexed components will be hard to find, but I doubt that a new bike would come with them.

I think this bike if from the 80's. It's a Fuji America

I think this bike if from the 80's. It's a Fuji America

I don't think that 6 speed trigger shifters exist.
The Paul Thumbies have a good rep but basic thumb shifters would be more cost-effective. Depends on how much you like your bar-cons.