As a web designer for SME's I often get requests to produce functionality that far exceeds the budget of my clients, however since discovering PHPJabbers 10 years ago I have to say that the apps and scripts they offer not only stretch my client's budget but make my life so much easier so I can worh smart not hard.
In nearly all cases I can find a pre-made PHPjabbers script that suites my client's needs and if they require some additional customisation PHPjabbers will do any bespoke customisation required at very reasonable rates.
Over the years I have asked for and received to my and my client's total satisfaction simple modifications to full blown bespoke alterations and additions.
I can particularly recommend their booking scripts that integrate into any web site and if you purchase the developers licence edition you are free to customised it to your hearts content.
Their Stiva Shopping Cart is a particularly great script for clients who are not IT geeks but who want the freedom to edit their own products and prices, for the money I personally think it great value.
Anyway enough of my rambling try out some of their stuff their support is second to none (Monday to Friday) and I am sure you will not be disappointed You can even try all their stuff for free on their demo sites allowing you to play with the software before you but it. Trust me I doubt if you will be disappointed.