Navionics a rip off

So the new to me trailer sailer I bought (from Vic) has Navionics Southeastern Australia loaded on the little micro SD card and I see no need to update for the areas I frequent around Sydney. The previous owner however did not have North East Australia which I now need. When I plug my little card into my laptop to update via the Navionics app that I have downloaded it doesn't reveal prices for updating but just before the last step does thank goodness warn that existing maps will be wiped before the updates are loaded.

This leaves me with the alternative of buying a North East Queensland card for $190p.a. and swapping cards as necessary rather than buying the whole of Australia card for $380 .
This is all per annum and I understand a few years ago before Garmin bought them out navionics was pretty much free or a token amount. I could use my tablet for which it is cheaper but there is no binnacle on the trailer sailer so the bulkhead mounted 12 inch screen is quite nice and brighter. It's a raymarine plotter.

Is there any good alternative that my Raymarine plotter will read and which I can place on my micro SD card?

Use a Windows 10 12 inch tablet with OpenCPN.

Thanks guys but as I said I don't have a binnacle on the trailer sailer and a tablet sliding around in gusts isn't practical. As the chartplotter on the boat is cut into a hole in the coach house rear bulkhead and is reasonably modern with a largish bright screen I was hoping that there would be some solution involving that.
I guess I will just have to put some velcro tape over the front of the chartplotter and then stick the tablet to the same spot temporarily whilst sailing. I don't have a tablet with a really really bright screen so a hood or a new expensive tablet will be required which is also a pain. Might just have to pay Navionics this time.

Hi Julesmoto, the fee for Navionics is just to get annual updates, it keeps working after a year. I have a 6 year old copy of navionics on my plotter (I will update soon) and I'm comfortable with that in my known waters. I keep an updated navionics version on a tablet and in addition, I have a current version of Open Cpn on my laptop.

For the convenience factor, you could bite the bullet and get the card you need, but only update it once every 2-5 years or whatever, therefore spreading the initial high cost over a longer period. If you're navigating into new areas, just check and compare the area beforehand against your current tablet app / openCpn or whatever, to ensure there's nothing obviously different.

Thanks Ramona, that Maiana is a tidy looking piece of kit, assume just usb module to pc with OpenCPN to nest the AIS data with the map(s)

Instead of a tablet you could buy an 'Android Auto' unit that designed to go in a car - they are amazing value. They install more neatly in places where CP were previously installed and generally have an external GPS antenna which may be helpful depending on where its installed. Just search ebay for android auto.Navionics (owned by Garmin) is more expensive than others, but the quality of the maps compared to many open source products is chalk and cheese especially for coastal and inland waters where you need accurate water depth. Buying the card version is a one-time cost and you can continue to use that version of the map for years. The subscription model (monthly fee) keeps your maps current and you keep paying and in most cases the waterways dont keep changing.

Yes the Android auto solution sounds interesting thanks. Should work just like a tablet so cheap Navionics. Water resistance and screen brightness would have to be checked for an external bulkhead mount however.
For now however I have just bought a new Navionics card for the TS as the chartplotter is much newer and external bulkhead mounted located unlike in my NS38.