<form method="post">
<div class="choose-term">
<button type="button" name="val" value="1"><input type="hidden" name="val" value="1">1 месяц</input></button>
<div class="price">8 000</div>
</div>
<div class="choose-term selected">
<button type="button" name="val" value="2"><input type="hidden" name="val" value="2">2 месяца</input></button>
<div class="price">16 000</div>
</div>
<div class="choose-term">
<button type="button" value="3" value="2"><input type="hidden" name="val" value="3">3 месяца</input></button>
<div class="price">24 000</div>
</div>
</form>