Health care is expensive in the US so student insurances get costly. However, here are some options that have better prices than the ones you mentioned:
AVI's Security Passport World is the best priced student insurance for EU citizens in my opinion. The price is 14 Euro/week so about 700 Euro for a full year.
Dr Walter's Pro Trip World Insurance with their additional insurance package is what I would recommend for non EU-students.
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Study Abroad Insurance
Study in the US
Universities and language schools in the US