yo...I went to Osaka & Kyoto in July...
Accomodation - i stayed at a little hotel called Rinkai or
something, you can try to find on the Internet. Accessible via
underground, only one stop from Osaka main station. Only 100+ (less
than 150) per night. Alternatively you may check out the hostels
there.
If you are travelling from Osaka to other parts (eg: Himeiji),
better to get a Japan Rail pass - cheaper than paying for
individual trip. Can get from Takashimaya upstairs - cost about
100+ for 5 days. This allow you unlimited travel on JR lines in
Osaka. do note the limitation though - not applicable for the
bullet trains and not applicable for underground (METRO) within
Osaka, but generally useful.
Shopping - there is a huge shopping centre above Osaka main station
(not Shin-Osaka but Osaka) - 13+ storeys of shopping. And, the
electronics is really cheap there, that is if you can bear with the
Japanese menu & interface. A PSP cost only about 200+ and
digital cameras are real steal. Clothes are also reasonable. Also,
if you are prepared to walk, there is a new building which you can
take a peek of the Osaka skyline from the viewing gallery.
Then there is the Osaka aquarium - accessible via metro from Osaka
main station, the aquarium is large - 4 storey high and the main
attraction - a whale shark. If you don't mind the hefty entrance,
its worth a look. Around the same area, there is a giant ferris
wheel - the tallest in Asia I think, quite a sight. there is also a
shopping centre near the aquarium where there is a Octupus ball
museum - which many stalls selling nothing but octupus balls that
you find in the outlets here in Singapore.
Of course, there is the Universal Studio at Osaka, accessible by
train and if you are lucky, you can ride on a special train painted
out in Sesame colors.
other places that I think is quite worth the visit - Himeiji
castle, Kobe, Kyoto if you have time. The railpass will come in
handy if you are visiting the above.
Food wise, they are abit on the high side, thats despite me
restricting myself to those simple ramen, it still cost about
S$4.00 per bowl....but if you are of legal age, you can drink
yourself silly from the vending machines ~ the beers are cheap ~ S$
2 plus can get a big can... 
