Hi Sangeetha,
If you can give me more information about what features are must have for you in your mobile phone, i can give you more specific suggestions. In the budget you have mentioned, i would suggest Nokia 6300. It is a very feature loaded phone, well within your budget and my personal favorite. I used to have a SonyEricsson walkman phone W810i. The sound clarity in Nokia 6300 was far superior that SonyEricsson W810i, though Nokia was a regular phone unlike W810i which is a walkman edition. So replaced W810i with Nokia 6300.
There are many other phones in your budget. You can check out some of them here:
Get Best Deals at The Mobile Store. From this site, you will get a fair idea about the market prices.
Do let us know what model you have purchased..
-Lakshmi