At 100% bonus, it was about 1.1cpm for transfers and 1.5cpm for buying/gifting.
At 50% bonus for buy / gift 1 mile = 2c on DL not worth it.
If she bought 1800$ last year, she got 120,000 miles (I did too, so I know).
Ask her to call DL, they can book an award on Air France or even Singapore to India for 120k miles.
SQ awards go away in 1 month, so hurry.
If you are going to buy miles, at least buy where they can be used.
Go to usairways.com and buy 40k miles for 1200$. 100% bonus gets you 80k
Then from your account gift her 40k miles for 1200$ 100% bonus = 80k
160k miles gets you in F for 2400$ plus taxes
or 120k miles gets you in C for 1800$
or get max 200k miles and use for 1c and 1Y award total 3000$
The promo ends today or tomorrow.
If each of you buys and gifts the other 50k you will get 400k for 6000$.
should cover all trips for a few months at least.
This is probably better in the US forum