If you want to go to Germany as well as Latvia, my suggestion would be to look for a cheap ticket to Germany and LCC it from there.

Frankfurt has edged out London as the cheapest place to fly into (or rather, out of) in Europe because the British government has slapped various "carbon"-taxes onto tickets departing from there.

So, look for a decently priced flight to Frankfurt, Munich, Hamburg, Stuttgart or Berlin, and then continue on on Air Baltic.

You can also fly Ryanair to Riga, but personally, I'd rather have bowel surgery in the woods with a stick than fly with that sorry excuse for an airline again.