First, I put your chosen parts into a PCPartPicker build. This is the Australian version so all pricing is in Australian dollars.
First, one of the things that a lot of people do is buy a cheap PSU thinking it is not an issue. It definitely is. You put the rest of the components at risk and the poor quality of power will actually make the system run worst. Casecom PSU's are not well known and what is known suggests that they are the bottom of the barrel. Chances are the specs on the PSU are not to be trusted. And you don't need a 550W, a good 350W will be just fine.
http://www.tomshardware.com/forum/362366-28-casecom-700w-opinion
I would suggest 8GB for RAM but it does depend on what games you will play. As well you should try to have at least two RAM sticks so the memory will run in dual channel. Not a big factor but still a factor. The GT 1030 won't support much in the way of more demanding games.
You will see a highlighted incompatibility in the build, that of a BIOS update for the G4560 required before the CPU can be used. BIOS 7.10 was release on 11-Oct-16 so a lot of mobos are still out there without this update. The consequence here is that the system won't boot with the G4560 without the update but you can't update the BIOS without a supported CPU. Yes, chicken and egg thing.
Tried to revise the build but I can't meet that pricing. I upgraded the mobo from H110 chipset to B250, removes BIOS issue. RAM went from 1x4GB to 2x4GB. Up the GPU to a GTX 1050 Ti, this will play most modern games well. I put a decent budget PSU in the build, the Antec VP series is reliable.
http://gpu.userbenchmark.com/Compare/Nvidia-GT-1030-vs-Nvidia-GTX-1050-Ti/m283726vs3649
Original Build
PCPartPicker part list:
https://au.pcpartpicker.com/list/F9yFFd
Price breakdown by merchant: https://au.pcpartpicker.com/list/F9yFFd/by_merchant/
CPU: Intel - Pentium G4560 3.5GHz Dual-Core Processor ($79.00 @ Shopping Express)
Motherboard: ASRock - H110M-HDV Micro ATX LGA1151 Motherboard ($69.00 @ Umart)
Memory: Crucial - 4GB (1 x 4GB) DDR4-2400 Memory ($59.00 @ Umart)
Storage: Western Digital - Caviar Blue 1TB 3.5" 7200RPM Internal Hard Drive ($59.00 @ Shopping Express)
Video Card: Gigabyte - GeForce GT 1030 2GB Low Profile Video Card ($98.00 @ Shopping Express)
Case: Cougar - Spike MicroATX Mini Tower Case ($75.00 @ Umart)
Power Supply: Antec - 500W ATX Power Supply ($58.00 @ Shopping Express)
Total: $497.00
Prices include shipping, taxes, and discounts when available
Generated by PCPartPicker 2017-12-16 03:58 AEDT+1100
Revised Build
PCPartPicker part list:
https://au.pcpartpicker.com/list/zCqd4C
Price breakdown by merchant: https://au.pcpartpicker.com/list/zCqd4C/by_merchant/
CPU: Intel - Pentium G4560 3.5GHz Dual-Core Processor ($79.00 @ Shopping Express)
Motherboard: MSI - B250M PRO-VD Micro ATX LGA1151 Motherboard ($98.00 @ Shopping Express)
Memory: Team - Vulcan 8GB (2 x 4GB) DDR4-2400 Memory ($129.00 @ Umart)
Storage: Western Digital - Caviar Blue 1TB 3.5" 7200RPM Internal Hard Drive ($59.00 @ Shopping Express)
Video Card: GALAX - GeForce GTX 1050 Ti 4GB OC Video Card ($179.00 @ Shopping Express)
Case: Cougar - Spike MicroATX Mini Tower Case ($75.00 @ Umart)
Power Supply: Antec - 500W ATX Power Supply ($58.00 @ Shopping Express)
Total: $677.00
Prices include shipping, taxes, and discounts when available
Generated by PCPartPicker 2017-12-16 04:02 AEDT+1100