Here are sample packages with choices of accommodation.
Personally, I strongly recommend Option 2 as it gives you the authentic experience of Southern Vietnam so you get the best value for your airfare expenses. However, Option 1 is also a good choice if you are pressed for time.
Prices could vary from time to time depending on availabilty of hotels and tour providers, but this is a quite a good estimate of the package costs.
TIP: Regular PAL flights usually cost 250 USD for Manila-Ho Chi Minh roundtrip. Cebu Pacific usually has lower fares but their flight times are around midnight so it is a matter of personal choice. I think the best solution is to book during seat sales, naturally. :)
Feel like giving Ho Chi Minh a spin? To know more, feel free to send me an email at firstname.lastname@example.org or leave a comment here.