ORDER BY with a UNION of disparate datasets (T-SQL)

I have a query that UNION's two somewhat similar datasets, but they both have some columns that are not present in the other (i.e., the columns have NULL values in the resulting UNION.)

The problem is, I need to ORDER the resulting data using those columns that only exist in one or the other set, to get the data in a friendly format for the software-side.

For example: Table1 has fields ID, Cat, Price. Table2 has fields ID, Name, Abbrv. The ID field is common between the two tables.

My query looks like something like this:

SELECT t1.ID, t1.Cat, t1.Price, NULL as Name, NULL as Abbrv FROM t1 
UNION 
SELECT t2.ID, NULL as Cat, NULL as Price, t2.Name, t2.Abbrv FROM t2 
ORDER BY Price DESC, Abbrv ASC 

The ORDER BY is where I'm stuck. The data looks like this:

100   Balls     1.53                       
200   Bubbles   1.24                       
100                     RedBall    101RB   
100                     BlueBall   102BB   
200                     RedWand    201RW   
200                     BlueWand   202BW   

...but I want it to look like this:

100   Balls     1.53                       
100                     RedBall    101RB   
100                     BlueBall   102BB   
200   Bubbles   1.24                       
200                     RedWand    201RW   
200                     BlueWand   202BW   

I'm hoping this can be done in T-SQL.