Tire places often have a few preferred brands where they offer some good deals while they have totally inflated prices for other brands. Again, it's worth to call around.
In the past I found some excellent deals at Pneu Bauriedl in Aadorf . They've been taken over by Vianor though, so I'm not sure if they're still as good.
I had a quick look at reifendirekt.de and it seems that for EUR 40 you get just some obscure asian "brand" tires. I would stay away from these. Tires are one of the few products where it's worth to pay for high quality brand name products.
If you want to replace just two tires I recommend that you stick with the brand and type that you already have. A car can behave quite nasty in a critical situation when driving with mixed tires.
Just don't try to do it in busy season when they're working 15 hours a day changing tyres and wheels over.
And do be careful when you source your tyres. For "common" sizes, you can end up with all sorts - check the speed rating and also troll, sorry, research car forums on the internerd for what others might be using.
I saved 500 francs on my last summer refit by doing this. My trusty tyre guy kept plugging away at tyres I did not want - as I checked a specific tyre for noise, economy and wear and wanted that one. Others with my car were very happy over the OEMs which came with the car.