Germany didn't use a green base coat. They used a red primer and applied a dark yellow base coat. You can apply dark yellow and red brown on your model to emulate a late WWII German camo.

Looks like you got a nice even coat on, so that's a positive start. As to what colour it should be, I'll leave that for others more familiar with the subject. As to being cheap, no harm in that. Not everybody can afford or be bothered paying for "proper" paints, if it works, it works. Now, filters are basically tints, or stains if you like, layers of colour to change the tones of the base. These can be done with anything from oils to pigments, to varying effect depending on the medium and technique used. If you do a search up top for "filters" you can get a better understanding of what the different types are and how to best use them and at what stage.

If you're going to continue brush painting, I'd recommend looking at Vallejos. They are very easy to work with and aren't terribly expensive. And if you have the patience to learn a little about mixing colours, you won't need to buy a whole bunch of them either.

Hopefully others will chime in with their 2 cents.

Kimmo

Are you entirely sure friend? I've seen photos and models of late-war Jagdpanthers and Tiger IIs with a basecoat of olive grun painted on them because of the shortage on available paint.

Pretty far! On my screen your color looks like a pastel blueish-green! Maybe turquoise. The German green was called Olive-grun, which is olive green.