*sigh* you know there is verifiable scientific evidence that formula at night will not make a baby sleep any longer or better? And that sleeping too deeply for too long is a SIDS risk?
There is no "best" formula, it has nothing to do with price. No one can look at your baby and see what they will have the least amount of side effects from, particularly given that the long term effects of formula are unknown. Todays formula are completely different than those of even 10 years ago.
However if you must use formula then you want a milk based formula, not soy. Soy is very strongly recommended against by most health organizations and governments world wide, though as usual guidelines in the US, Canada, etc lag behind.
The good about hydrolyzed is that it is less likely to cause allergies and a few other problems. However those are never sweetened with lactose and formula sweetened sucrose (like corn syrup) are more likely to cause tooth decay. And corn is an allergen in and of itself.
http://www.prematureoptimism.com/linkBlog/?p=65
When It Has to be Formula: Optimizing the Health of Your Formula-Fed Baby
http://www.naturalfamilyonline.com/go/index.php/226/optimize-health-formula-fed-baby/
Bottle-feeding Index
http://askdrsears.com/html/0/T000100.asp
EVALUATING THE SAFETY OF NEW INGREDIENTS
http://www.nap.edu/openbook.php?isbn=0309091500
Formula for allergenic babies
http://www.nap.edu/openbook.php?isbn=0309091500