@koret,
There are a couple factors to consider:
You won't have to pay the penalty for not having coverage if your share of the premium (after any employer contributions and subsidies) would exceed 8 percent of your income. This is one of several exemptions to the penalty. Unlike the income test for premium subsidies, the premium amount used as the basis for this calculation can include premiums for dependents.
To qualify under the Affordable Care Act, policies have to provide minimum essential coverage and minimum actuarial value [in most cases the minimum actuarial value is 60% (also called Bronze level)]. A high deductible plan you purchase on your own may not meet these requirements.