JSFiddle - React, Tailwind, and code Playground

HTML

<div class="container">
    <div class="selectBox chosenamountselect">
        <span class="selected"></span>
        <span class="selectArrow">&#9660;</span>
        <div class="selectOptions">
            <span class="selectOption" value="100">&pound;100</span>
            <span class="selectOption" value="125">&pound;125</span>
            <span class="selectOption" value="150">&pound;150</span>
            <span class="selectOption" value="175">&pound;175</span>
            <span class="selectOption" value="200">&pound;200</span>
            <span class="selectOption" value="225">&pound;225</span>
            <span class="selectOption" value="250">&pound;250</span>
            <span class="selectOption" value="275">&pound;275</span>
            <span class="selectOption" value="300">&pound;300</span>
            <span class="selectOption" value="325">&pound;325</span>
            <span class="selectOption" value="350">&pound;350</span>
            <span class="selectOption" value="375">&pound;375</span>
            <span class="selectOption" value="400">&pound;400</span>
        </div>
    </div>
</div>

CSS

div.container {
    width: 400px;
    height: 300px;
    overflow-x: hidden;
    overflow-y: visible;
    margin-left: auto;
    margin-right: auto;
}

div.selectBox {
    position: relative;
    display: inline-block;
    cursor: default;
    text-align: left;
    line-height: 30px;
    clear: both;
    color: #888;
}

span.selected {
    width: 167px;
    text-indent: 20px;
    border: 1px solid #ccc;
    border-right: none;
    border-top-left-radius: 5px;
    border-bottom-left-radius: 5px;
    background: #f6f6f6;
    overflow: hidden;
}

span.selectArrow {
    width: 30px;
    border: 1px solid #60abf8;
    border-top-right-radius: 5px;
    border-bottom-right-radius: 5px;
    text-align: center;
    font-size: 20px;
    -webkit-user-select: none;
    -khtml-user-select: none;
    -moz-user-select: none;
    -o-user-select: none;
    user-select: none;
    background: #4096ee;
}

span.selectArrow,span.selected {
    position: relative;
    float: left;
    height: 30px;
    z-index: 1;
}

div.selectOptions {
    position: absolute;
    top: 28px;
    left: 0;
    width: 198px;
    border: 1px solid #ccc;
    border-bottom-right-radius: 5px;
    border-bottom-left-radius: 5px;
    overflow: hidden;
    background: #f6f6f6;
    padding-top: 2px;
    display: none;
}

span.selectOption {
    display: block;
    width: 80%;
    line-height: 20px;
    padding: 5px 10%;
}

span.selectOption:hover {
    color: #f6f6f6;
    background: #4096ee;    
}

JavaScript

$(document).ready(function() {
                enableSelectBoxes();
            });
            
            function enableSelectBoxes(){
                $('div.selectBox').each(function(){
                    $(this).children('span.selected').html($(this).children('div.selectOptions').children('span.selectOption:first').html());
                    $(this).attr('value',$(this).children('div.selectOptions').children('span.selectOption:first').attr('value'));
                    
                    $(this).children('span.selected,span.selectArrow').click(function(){
                        if($(this).parent().children('div.selectOptions').css('display') == 'none'){
                            $(this).parent().children('div.selectOptions').css('display','block');
                        }
                        else
                        {
                            $(this).parent().children('div.selectOptions').css('display','none');
                        }
                    });
                    
                    $(this).find('span.selectOption').click(function(){
                        $(this).parent().css('display','none');
                        $(this).closest('div.selectBox').attr('value',$(this).attr('value'));
                        $(this).parent().siblings('span.selected').html($(this).html());
                    });
                });                
            }