When the movie is half over, popcorn sells for half price. Full price popcorn is $3.50, and drinks are $1.35. Determine the cost for purchasing 3 orders of popcorn and 3 drinks when the movie is half over.

When the movie is half over, popcorn is sold at half price.

The full price of popcorn is $3.50, so the half price is:
\[
\text{Half price popcorn} = \frac{3.50}{2} = 1.75
\]

The price of one drink is $1.35.

Now, we can calculate the total cost for purchasing 3 orders of popcorn and 3 drinks.

**Total cost for popcorn:**
\[
\text{Cost of 3 popcorns} = 3 \times 1.75 = 5.25
\]

**Total cost for drinks:**
\[
\text{Cost of 3 drinks} = 3 \times 1.35 = 4.05
\]

**Total cost:**
\[
\text{Total cost} = \text{Cost of popcorn} + \text{Cost of drinks} = 5.25 + 4.05 = 9.30
\]

Thus, the total cost for purchasing 3 orders of popcorn and 3 drinks when the movie is half over is:
\[
\boxed{9.30}
\]