How can I set a price for custom text? - prestashop

Question

Is there a way to add price if the client add the custom text (the one inside the Options section when you add the product) in a product? or have I to add it by product combinations (adding a lot of combinations)?
With the input radio I can't control what the user will do and I can't set it as "required" because it must be a free choice.
{block name='product_customization_form'}
<form method="post" action="{$product.url}" enctype="multipart/form-data">
<ul class="clearfix">
{foreach from=$customizations.fields item="field"}
<li class="product-customization-item">
<label> {$field.label}</label>
{if $field.type == 'text'}
<textarea placeholder="{l s='Your message here' d='Shop.Forms.Help'}" class="product-message" maxlength="250" {if $field.required} required {/if} name="{$field.input_name}"></textarea>
<small class="float-xs-right">{l s='250 char. max' d='Shop.Forms.Help'}</small>
{if $field.text !== ''}
<h6 class="customization-message">{l s='Your customization:' d='Shop.Theme.Catalog'}
<label>{$field.text}</label>
</h6>
{/if}
</li>
{/foreach}
</ul>
<div class="clearfix">
<button class="btn btn-primary float-xs-right" type="submit" name="submitCustomizedData">{l s='Save Customization' d='Shop.Theme.Actions'}</button>
</div>
</form>
{/block}

Answer 1

The best way to achieve this would be to have two product combinations:
With custom text (+$0)
Without custom text (+$1.00)
Next, add some custom Javascript code to your product page (the proper way would be via a module) that would do the following:
Check if the customization textarea element is present on the page
Check if it is empty or not
If not, force the combination ID to the right ID (the "with customization" version)
That's it.
That way, the buyer won't have to select any option, they just have to fill a custom text if they would like to and the price will adjust automatically in their shopping cart.
I hope this helps!