Great initiative ! I can give our perspective that may help.
I guess in part it depends on what you are aiming for with Digital Manufacturing and how big your shoestring is.
There are plenty of definitions of what a Production Intelligence Journey should look like, at Trelleborg we have defined 5 major steps, Connected, Visible, Predictive, Adaptive and Intelligent. We have different plants at different places on this journey ( most at the beginning ), however, the stated goal is just to get all plants connected and visible over the next 18-24 months ( complete step 2 ).
Although the Plant I am based at is reasonably well positioned ( we have had SCADA connected systems for 10 years ) we are looking at a low cost way to get other plants to the connected and visible level ( displaying OEE from automatically collected machine signals for example ).
To that end we are trialling IOT Devices from Advantech ( there are others available ) for +/- £150 you can buy a device with 12 inputs - in its simplest form this will give us a "Machine in Production" and "Cycle Completed" signal from 6 machines - £25 per machine.
If you are on a shoestring you might not have an IT Expert ( very capable post Grad students are available for around £27k per year in Leicester - or use students still studying as we have done from Nottingham University ) or an account with Microsoft / Google / Amazon clouds - however, these Advantech devices can connect directly to Azure ( we use Microsoft ) and from there you can use something like Power BI to display the results.
We are currently moving from our SCADA system to Kepware KepserverEX - which is not too expensive ( free equivalent available from Advantech !) ... that will act as the interface to all our connected devices and PLC's and then to which ever software we choose to use.
Once you've connected your devices to your machines, there are lots of software vendors willing to take those signals ( if you don't have the time / resource to do it yourself ) and turn them into valuable information. Some companies offer free proof of concepts ( Visual Factories for example ) and most will do a SaaS ( Software as a Service ) contract - so no up front costs. This is ideal as the benefits of simply visualising and increasing OEE should far out weight any costs for software.
I would suggest whatever you do, keep control / access to your data, as you've no doubt heard many times, data is the new oil / gold and it is yours, keep hold of it ! Don't set your sights too high, maybe a good start is to simply say that you will connect to machines and display what you can as we have done (there is a lot going on in this space - maybe start slow and see what happens and for sure whatever happens needs connections to machines so starting there is always a good place ). After that for £150 for a single device, a free proof of concept from a software vendor and you could be actively displaying OEE from 6 machines within 2 weeks ( full OEE needs some operator input as well ) for a Shoestring. In one of our factories we had a proof of concept up and running in 10 days from almost scratch.
Just to say that although Trelleborg is a large company, it operates in a very decentralised manner ( which has its good and bad points ) so we are effectively made up of many SME's.