One of the fundamental areas of learning when teaching oneself a foreign language is grammar. This is very hard to pick up from a workbook. So I suggest picking up a used textbook. I personally was not picky, I just played around on amazon and stumbled across one for 1 cent. Yep 1 cent, plus a few bucks shipping. Sure it is a bit outdated it talks in terms of old German currency lol, but the concepts are the same, and I have found it very useful. You can also pick up the textbooks that are used in the German integration courses for pretty cheap.
Kontakte- A communicative Approach second edition by Terrel, Tschirner, Nikolai and Genzmer ISBN:0-07-063787-3
Integration course books: (you can buy individual workbook and textbook, or a combo book )
Themen 1 aktuell Kursbook (textbook) ISBN: 978-3-19-001690-7 (I paid about 14 new)
Themen 1 aktuell arbeitsbuch (workbook) ISBN: 978-3-19-011690-4 (I paid about 11 new)
Themen 1 aktuell Glossar (Glossary) ISBN: 978-3-19-081690-3 (I paid about 6)
Level a2: (Same prices as a1 books)
Themen 2 aktuell Kursbook (Textbook) ISBN: 978-3-19-001691-4
Themen 2 aktuell arbeitsbuch (workbook) ISBN: 3-19-011691-1
Themen 2 aktuell Glossar (Glossary) ISBN: 978-3-19-251691-7
I think workbooks are very helpful in learning a foreign language. It actually gives you hands on use of the grammatical concepts you have read about. I think they are the key to self study.
German in 10 minutes a day ISBN: 978-0-944502-20-4 (I bought mine new for 20, but see them used all the time on amazon)
Berlitz basic German Workbook ISBN: 981-246697-5 (found new on amazon from a private seller for 6 bucks)
Also if you are in Germany there is a steady supply of workbooks for German kids. I always keep my eye out at Aldi and Lidl. They have some great workbooks. They are based one grade level, but just flip through till you find one closest to your level of German. I for instance stick around grade 4-6. Once you get higher they start to loose me :)
It does not matter how good your grammar is without a word base to use it with. I use both a photo and traditional dictionary. It is definitely worth it to splurge a bit and buy yourself a good dictionary. Make sure it also has a section with German- English. Mine also has a great grammar section in the back
German- English Visual Dictionary ISBN: 978-0-7566-1295-5
Collins German Concise Dictionary ISBN: 978-0-06-114183-6
4. Grammar related books
You can find tons of books related to German grammar. These break it down a bit more then textbooks.
English Grammar for Students of German by Zarach and Melin ISBN: 0-934034-23-0
Barrons 501 German verbs (sorry no ISBN)
The first is great for comparing English and German grammar, the second breaks down the most commonly used verbs into every verb conjugation.
As your German improves it is great to start reading in German. Look for newspapers, magazines, and kids books.
I pick up the cheap women's magazines and read them.
I also love kids books like Das Grosse Buch Der 1001 Fragen & Antworten
I have also heard there are some magazines written in German for people who are studying the language. Deutche Perfekt id one I believe, but I haven't found it in any stores. If anyone knows who carries it please do let me know.
I hope this helps. Feel free to contact me with any questions. And if you know a good resource for learning German leave me a comment.
Next time I will write about learning German online :)