Hi,
For the moment there is no such option to remove the column but it's a good idea that I put in my TODO list.
You can remove the column by editing the view "productmarket | form_price".
You will have to remove
			<th class="title"><?php
				echo JText::_('PRICE_WITH_TAX');
			?></th>Replace
			<td class="hikam_price">
				<input type="hidden" name="price[<?php echo $i;?>][price_id]" value="<?php echo @$price->price_id;?>" />
				<input size="10" type="text" id="hikamarket_price_<?php echo $i;?>_price" name="price[<?php echo $i;?>][price_value]" value="<?php echo @$price->price_value; ?>" onchange="window.productMgr.updatePrice(<?php echo $i; ?>, false)" />
			</td>
			<td class="hikam_price">
				<input size="10" type="text" id="hikamarket_price_<?php echo $i;?>_with_tax" name="price_with_tax_<?php echo $i;?>" value="<?php echo @$price->price_value_with_tax; ?>" onchange="window.productMgr.updatePrice(<?php echo $i; ?>, true)"/>
			</td>
By:
			<td class="hikam_price">
				<input type="hidden" name="price[<?php echo $i;?>][price_id]" value="<?php echo @$price->price_id;?>" />
				<input size="10" type="text" id="hikamarket_price_<?php echo $i;?>_price" name="price[<?php echo $i;?>][price_value]" value="<?php echo @$price->price_value; ?>" />
			</td>
And also replace:
			<td class="hikam_price">
				<input type="hidden" name="price[{id}][price_id]" value="" />
				<input size="10" type="text" id="hikamarket_price_{id}_price" name="price[{id}][price_value]" value="" onchange="window.productMgr.updatePrice({id}, false)" />
			</td>
			<td class="hikam_price"><input size="10" type="text" id="hikamarket_price_{id}_with_tax" value="" onchange="window.productMgr.updatePrice({id}, false)"/></td>By:
			<td class="hikam_price">
				<input type="hidden" name="price[{id}][price_id]" value="" />
				<input size="10" type="text" id="hikamarket_price_{id}_price" name="price[{id}][price_value]" value="" />
			</td>
Best regards,