How to shop for wines

[acaines]

My wife and I like to have a bottle of wine every once in a while. Neither of us are experienced, but we know what we like. We tend to like wines which are on the sweet side, but not too sweet. Berringer makes a white Merlot which we really like, but there are other wines available and since variety is the spice of life, we want to expand our palette. The problem is we don't buy wine all that often. Therefore, we don't want to ruin a nice evening together by buying a wine we don't like. I do look at price... anything that sells for less than $5 for 750ml I avoid. Usual price range is $6-$15/bottle, but definitely open to higher range for something really special. Would also like to venture into wines from other countries like Chile, Australia, Germany, Italy…
Any suggestions?

Some wines we have tried:
White Merlot-- Our current favorite.
Chardonnay-- A bit acidic for our tastes.
White Zinfandel-- Nice, but we like white Merlot better because of its fruitier taste.
Merlot-- Not bad... a bit heavy for our tastes.
Muscat-- Nice dessert wine.
[Soft]Chenin Blanc-- Enjoyable, however a little sweeter than we like.

[acaines]

Update...
Just found the FAQs. Very informative. Makes me think I am not the first to ask the questions I have asked.

[Innkeeper]

Still free free to ask questions here too, but we're glad you found the FAQs.

FYI Chenin Blanc like Riesling comes in many shades including shades of sweetness. Having said that, Riesling is much more widely available. It is found in this the USA in New York, Michigan, Washington State, California, and elsewhere. It is also the native drink of Germany, and very popular in Austria, and the Alsace Region of France. Australia is coming on strong.

Chenin Blanc is found primariy in the Loire Region of France (Vouvray, and Savennieres), South Africa (sometimes called Steen), and here and there in California.

All are available in the USA and Canada. Try a Vouvray; I think you'll like it. Very generally speaking, the less expensive it is the sweeter it is.