First of all there are very various stages of development within the Whampoa Garden (you have Whampoa estate, Whampoa garden....), second of all it is local but you will find a fair amount of foreigners living there and finally not all locals are noisy and cook smelly food....the stereotypes on this forum are really really annoying sometimes.
From Whampoa you do not take the MTR to Kowloon Tong but Minibus nbre 2 to Festival Walk.
That being said, the prices in Hunghom have gone up in recent years (like most of HK). You can still find accomodation below 10K for sure but some cheaper and / or well located area to consider within 30 mn of Kowloon Tong could be To Ka Wan (next to HungHom and a lot more local), Olympic (10K will be hard but doable), ShamShuiPo/MongKok/Prince Edward (rather old buildings in poor conditions BUT a few properties are quite nice), Diamon Hill (a few nice estates), Tseun Kwan O, Tseun Wan as also a few good buildings, Shatin...the list is basically endless.